Restrictions on steel imports appear to have gained a new political salience following the resignation of Lord Geidt, the Prime Minister’s independent adviser on ministerial standards.

Lord Geidt’s resignation letter did not explicitly state which issue had forced him to quit but the Prime Minister’s reply referred to a matter concerning the Trade Remedies Authority (TRA) that had previously had cross-party support.

This has widely been taken to mean the question of extending quotas on steel imports, with a decision due by the end of June.

The TRA itself said the Prime Minister’s letter “appears” to refer to the steel safeguards case, although Downing Street has refused to comment.

The TRA was established after Brexit by the Trade Act 2021 to help defend the UK’s economic interests from unfair international trading practices, and makes recommendations on tariffs and quotas where appropriate.

The UK carried over the steel safeguards originally imposed by the EU when it left the bloc in 2020, and in June 2021 the TRA recommended revoking some of them as there was either no evidence of increased imports or the tariffs were harming the competitiveness of UK companies that use steel.

But the backlash from steel producers led then-trade secretary Liz Truss to overrule the TRA and continue most of the safeguards for another year, apparently due to concern about imports from China.

That decision is now up for review again, with Labour pushing for the safeguards to continue. As recently as Thursday morning, shadow trade secretary Nick Thomas-Symonds urged the Government to make a decision “today”.

In response, trade minister Penny Mordaunt would say only that the decision was expected “very shortly”.

Overruling the TRA again would further cast doubt on the agency’s purpose, with commentator Sam Lowe describing the decision in June 2021 as having left the body “kneecapped”, and suggested the Government’s commitment to free trade was conditional on politically important industries such as steel being protected.

It would also potentially breach World Trade Organisation (WTO) rules, which is why Lord Geidt appears to have objected given that the Ministerial Code requires ministers to comply with the law.

In his resignation, Lord Gedit referred to “measures which risk a deliberate and purposeful breach of the Ministerial Code” that had placed him in “an impossible and odious position”.

In his reply to Lord Geidt, Boris Johnson said the decision under consideration by the Government “would be in line with our domestic law but might be seen to conflict with our obligations under the WTO”.

A spokesperson for the TRA said: “We have been made aware of the Prime Minister’s letter to Lord Geidt today.

“The Trade Remedies Authority case to which the letter appears to refer was ‘called in’ by the Government earlier this year, meaning that the Government holds full decision-making authority in relation to the case.

“The TRA has carried out analysis under the Government’s direction and we provided a Report of Findings to the Secretary of State for International Trade on June 1. The Report of Findings is an analytical piece of work designed to inform Government decision-making and does not contain recommendations from the TRA.”