Check your Bank of England statistical returns

Who sends BT and EL

The Bank of England collects statistics from the banks and building societies in the UK banking sector. Its statistical reporting page says everyone needs to submit two returns. Both go to the Bank through BEEDS, its data collection portal, as XBRL-XML files on its statistics taxonomy.

• Balance sheet return (BT)All 68 checks runWhat the firm holds and owes on the last day of the period: assets such as cash, loans and investments, and liabilities such as deposits and capital, split by currency (sterling, euro and other) and by the kind of counterparty, such as banks, the UK private sector or the public sector. Larger firms send it monthly (total assets over £3 billion, among other tests), the rest quarterly. The Bank uses it in its money and credit statistics, and the ONS in the national accounts (Bank of England, form BT).
• Eligible liabilities return (EL)All 18 checks runThe firm's eligible liabilities, reported from its own accounting records rather than on the statistical basis of the other forms. The Bank uses them for the Bank of England Levy and the PRA's fees. Firms with eligible liabilities over £400 million for two quarters running send it monthly, the rest quarterly. The Bank's statistical reporting page calls it ELS; its form page and the taxonomy call it EL (Bank of England, form EL).

What else a firm sends depends on the nature and scale of its business, by the Bank's reporting thresholds: 29 more forms, such as the profit and loss return (PL), effective rates return (ER) and quarterly derivatives return (DQ). Line4 Check runs them all, and the all-forms file that carries every form at once.

After the Statistical Utility

In 2022 the Bank made its own Statistical Utility tool available to help firms move their statistical returns to XBRL, and in Green Notice 2024/01 it said the tool would be withdrawn with the next update to its data point model. Its Statistical Notice 2026/05 (3 June 2026) says the tool “will no longer be supported as part of this taxonomy update”, taxonomy 1.3.1, which is for live submissions of end-May 2026 data, due from mid-June 2026. Firms that used it “should make alternative arrangements”, such as a recognised software provider or an internal solution that makes valid XBRL files.

Line4 Check does not make the file, and does not send it to the Bank. Whatever makes your file, you can run the Bank's own validation rules on it here, in your browser, before you submit it through BEEDS: the same rules the Bank publishes with the taxonomy, with each failure in plain words.

Checks run, form by form

The Bank of England lists its validation rules for each form in one workbook, and writes almost all of them into the taxonomy package as XBRL formulas. A form's active checks are those the Bank lists for it as XBRL rules, less any the package switches off. Counted once each, Line4 Check runs 1,288 of the Bank's 1,290 active rules; the table counts them form by form, as a rule in a form and in the all-forms file counts once for each. Line4 Check runs a check only once it is proven on test files, check by check. Before a check ships, it is run on the Bank's own sample for its form and on test files built so that every check actually runs, and its results are compared, check by check, with an open-source reference processor: the same outcome, tested the same number of times, on every test file of the form. A check that does not match exactly does not ship.

Every report carries the same line, for example: “This free check runs all 68 of the Bank of England's active validation checks for its balance sheet return (BT) on the statistics taxonomy 1.3.1, every one proven on test files, check by check (13 test files), plus 47 rules of the Bank's XBRL Filing Manual v1.0.1 in full and 2 in part. It is not a substitute for the validation the Bank runs when you submit the return.”

What is held back, and why

4 of the Bank's 2,461 active checks for these forms do not run, counted form by form: 2 checks, each in its own form and in the all-forms file. Line4 Check never counts a check it does not run as passed.

• Held back: the reference results were not consistent between runs: 4Before a check ships, its results on every test file are compared, check by check, with an open-source reference processor. For these checks the reference processor tested them a different number of times on the same test file in different runs. Line4 gives the same outcome as every one of those runs, but a check only ships when it matches exactly, so these stay out until the reference results are the same every time.BG: 1 of its 10 (BG_v0002); CE: 1 of its 45 (CE_v0040); ALL: 2 of its 1,283 (BG_v0002, CE_v0040).

The coverage ledger lists every check, run or not, form by form, with each check held back by its code and the reason.

The Bank's list of validations also has 2 rules for these forms, counted form by form, that it does not write into its XBRL. They have no formula to run, in Line4 Check or in any XBRL processor, and are not among the 2,461 above. Returns not built on the Bank's statistics taxonomy are not checked here.

How the proof works: the test files for each form are the Bank's own sample, test copies of it with facts changed, and synthetic returns built to fill its templates (32 samples, 197 test copies and 192 synthetic returns, 421 files in all). Every check is run on every file, and its results are compared, check by check, with an open-source reference processor. A check runs here only when the two agree exactly on all of them. Line4 Check is a prototype of the Line4 validation engine, not certified software.

The Bank's filing rules

The Bank's 1.3.1 release note says its XBRL Filing Manual (v1.0.1) complements and replaces the old statistics filing manual, for how the instance itself is written. Line4 Check checks 47 of its rules in full and 2 in part on every form, under the Bank's own numbers: the file name and encoding, the schemaRef and entry point, the filing indicators, the entity identifier, contexts and dates, units and decimals, nil and duplicate facts, and more. A broken MUST rule is an error and a broken SHOULD rule a warning, each shown in plain words first, then its number.

Checked in full, by the Bank's numbers: 1.1, 1.4, 1.5.(a), 1.6.(a), 1.6.(c), 1.6.1, 1.6.2, 1.6.3, 1.7.(b), 1.7.1, 1.13, 1.14, 1.15, 2.1, 2.2, 2.4, 2.6, 2.7.(a), 2.7.(b), 2.8.(a), 2.9, 2.10.(a), 2.10.(b), 2.11, 2.13, 2.14, 2.15, 2.16, 2.16.1, 2.17, 2.18.(a), 2.18, 2.19, 2.21, 2.22, 2.23, 2.24, 2.25, 2.26, 3.1.(a), 3.2.(a), 3.4, 3.5, 3.7, 3.9, 3.10 and 3.11.

Checked in part:

• Rule 1.5.(b), the schemaRef is checked against the form's entry point; the reference date is not: the release note makes taxonomy 1.3.1 effective for live submissions of end-May 2026 data, and does not say which taxonomy a resubmission of an earlier period uses.
• Rule 1.9, XBRL 2.1, XML Schema and XBRL Dimensions validity as far as the reader sees it (contexts, units, numbers, dates, booleans, coded values, decimals, ids, datapoints of the module); not a full schema validation, and not the extensible enumeration lists, which the rule files do not carry.

Not checked:

• Rule 1.10, the codes and type of codes: the taxonomy's own validation rules check them.
• Rule 1.12, a complete report: an instance does not say what the firm should have reported.
• Rule 2.5, what the values mean: an instance does not say it.
• Rule 2.6.(a), meaning in ids: an instance does not say it.
• Rule 2.6.(b), the length of ids: the manual gives no measure.
• Rule 2.8.(b), the entity's registration with the Bank: an instance does not say it.
• Rule 2.18.(b), no rounding or truncation: the manual gives no measure.
• Rule 2.18.(c), a realistic accuracy: the manual gives no measure.
• Rule 3.1.(b), not checked yet: the engine does not compare an amount's unit with its Currency with significant liabilities (CUS) member.
• Rule 3.1.(c), not checked yet: the engine does not compare an amount's unit with its Currency with significant liabilities (CUS) member.
• Rule 3.2.(b), percentages as fractions: the manual gives no measure.
• Rule 3.3, what the values mean: an instance does not say it.
• Rule 3.8, the length of strings: the manual gives no measure.

Which taxonomy: 1.3.1

The Bank published the Bank of England Statistics Taxonomy 1.3.1 with its release note of December 2025. It is for live submissions of end-May 2026 data, due from mid-June 2026. It replaces 1.3.0 and is not backwards compatible with it: the Bank says a file made on 1.3.0 is not valid for submission under 1.3.1 (Statistical Notice 2026/05). The reporting requirements themselves do not change. The 32 entry points here are every one in the package, and a file names one in its schemaRef, such as http://www.bankofengland.co.uk/data/xbrl/fws/banking_stat/stats/2025-10-21/mod/bt.xsd. Line4 Check matches that address exactly, so a file is only ever checked against the rules of the form and release it names.

How it works

1. 01Your browser downloads the engine and the rulesThe Line4 engine with its XBRL-XML reader is compiled to WebAssembly (500 KB). Only the rules of the form you check are downloaded: the Bank’s balance sheet rules are 40 KB, its eligible liabilities rules 13 KB. Your browser keeps them for next time.
2. 02Your file is opened on your computerThe XBRL-XML instance is read inside the browser tab, in a background worker so the page stays responsive. Its schemaRef says which form and taxonomy release it is. Nothing is uploaded.
3. 03The checks run and are listedEach failed check is listed by template, in plain words, with the value found, the value expected and the Bank’s rule code; broken filing rules come first, in a card of their own. Download it all as a CSV.

Questions