The UK government is undermining national security by delaying the introduction of publicly available share ownership registers in Britain’s major tax havens such as the British Virgin Islands, the foreign affairs select committee has said.

During a general inquiry into the relationship between the UK and its overseas territories, the MPs on the committee discovered that the Foreign Office planned to delay the introduction of publicly available beneficial share ownership registers until 2023, three years after the deadline MPs believed they had set. Public registers are seen as critical by campaigners for cracking down on money laundering, corruption and tax evasion, including by leaders of authoritarian governments.

The Commons believed it had set a clear deadline of the end of 2020 after a cross-party backbench rebellion during last year’s passage of the sanctions and anti-money laundering bill.

But the government – without consulting parliament – interpreted the amendment to the bill as merely requiring ministers to state by the 2020 deadline when they would introduce the registers, and then unilaterally set the date for their introduction as the end of 2023, after the next election.

The overseas territories, anxious to protect the income associated with secret tax havens, had warned of a major constitutional rupture with London if the 2020 date were imposed.

In its report the foreign affairs select committee states: “We profoundly regret that public registers may not be published before 2023. It is simply not acceptable that this will be long after the deadline set out in the act.”

They point out that the government “has judged public registers of beneficial ownership to be a matter of national security”.

“Those who seek to undermine our security and that of our allies must not be able to use the OTs to launder their funds. We cannot wait until public registers are a global norm and we cannot let considerations of competitiveness prevent us from taking action now. The lowest common denominator is not enough,” the report says.

It is understood that the Labour frontbench is considering tabling amendments to the finance bill to make it clear that the originally intended 2020 deadline is being restored.

The report also calls on ministers to set a date by which the overseas territories are required to legalise same-sex marriage or risk facing the law being imposed by Westminster.

The FCO rejected any suggestion that it has defied the will of parliament by setting a date after the next general election for the introduction of public registers.

It said in a statement: “As set out clearly in the act, we will prepare draft legislation by the end of 2020, with all overseas territories (OTs) expected to have fully functioning public registers in place by the end of 2023. This is part of the government’s call for all countries to make public registers the global norm by 2023. Our approach both respects the will of parliament and delivers this in a way that is fair and proportionate to all our OTs.”