The government has been accused of defying parliament by delaying plans to require British tax havens such as the British Virgin Islands to bring in public registers that reveal the true identity of owners of companies sheltering assets.

Foreign Office ministers have caved in after a rebellion in the British overseas territories, including threats to take the government to court or even to secede from the UK. The British-administered tax shelters have always been seen as a blight on the Conservative claim to be fighting the multibillion-pound corruption industry.

The Foreign Office told the overseas territories that they did not need to introduce compulsory public registers until 2023 – three years after the date MPs had thought they had set by law in a fractious debate last May.

The date means public registers in the overseas territories, seen as critical to winding down tax avoidance, will not be introduced until a decade after David Cameron first raised the issue as a flagship anti-corruption measure ahead of the UK chairmanship of the G7 industrialised economies.

A cross-party alliance of MPs last May, led by the former Conservative cabinet minister Andrew Mitchell and the former chair of the public accounts committee Margaret Hodge, had forced the government to concede that it would introduce an order in council by 2020 requiring public registers to be set up if the overseas territories had not done so voluntarily by that date.

Hodge said: “This new timetable is a sleight of hand and an attempt to ignore the clear will of parliament. It was clear not that that order in council should be introduced in 2020, but the public register. We will have to consider what steps are taken to restore what was intended.”

Mitchell said: “It is good that the overseas territories and Foreign Office accept that important change is coming. Nevertheless, parliament will be surprised at any move to put back the implementation date. I am sure the overseas territories and the Foreign Office will not want to challenge parliament by revisiting an issue on which they were not successful.”

Chris Bryant, a Labour member of the foreign affairs select committee, said: “This timetable is not what parliament thought they were getting when they discussed this. The government has dragged its heels on this issue and this seems yet another unjustified delay. It as if the government has become the Department for Procrastination. It means the British overseas territories remain Britain’s achilles heel when it comes to financial corruption, money laundering and dodgy money.”

He pointed out the amendment to the sanctions and money laundering bill that was passed set a deadline of 2020 for the order in council. MPs pushing this motion made clear this was also seen as the deadline for the introduction of the public register, he said,and that was also the understanding in the overseas territories.

Shadow foreign office minister Helen Goodman said: “The government have tried and tried to avoid and delay this. But the law is clear. This takes their contempt for parliament to a new low.”

Ministers appear to have backtracked after the 2020 deadline caused outrage in the overseas territories, which are worried that this timetable for disclosure requirements would lead to a flood of business decamping to other more secretive tax havens. Territories including the Cayman Islands argued that public registers should only be compulsory when they are introduced worldwide.

The 2023 timetable was set out by Lord Ahmad, the minister responsible for the overseas territories, in evidence to the foreign affairs select committee. He told the committee: “It is our intention that if by 2020 there is no public register, for whatever territory, we will then issue an order in council, which will then have a requirement for an operational public register by 2023.”

He said the only obligation provided in the legislation was to pass an order in council by 2020, but no date for the actual introduction of the public register was set. He has formally advised the overseas territories of this new timetable in writing following a meeting of the joint ministerial council, the body that brings together ministers and the overseas territories.

Tax transparency campaigners have argued for more than a decade that only a public register will force companies to end the systematic tax evasion that lies at the heart of the economies of the overseas territories. A public register would be available to tax experts and reporters, not just law enforcement officials.

“Every year that goes by gives more opportunity for dirty money to flow through the UK’s overseas territories and crown dependencies undetected,” said Rachel Davies Teka, the head of advocacy at Transparency International UK. “It will be disappointing if the overseas territories do not take the initiative to implement public registers on their own terms before the 2020 deadline.”

The overseas territories are already in the process of setting up registers of beneficial ownership of companies that will only be available to law enforcement officers on request.

Hodge said the cross-party alliance against tax havens had, in private negotiation with ministers last year, agreed to defer the introduction of the public register by a year to 2020 after ministers argued the territories were struggling to cope in the wake of hurricanes. The new timetable sets the date for the public register beyond the next UK election, opening the possibility that the timetable could be deferred further.