The UK's Crown Dependencies have set out a timetable to open up on company ownership.Read more
BBC News Online
Changes to laws in the Crown dependencies will not guarantee significantly more tax is paid in the European Union or in developing countries, Oxfam has warned.
In its report Not Enough Substance?, the charity has assessed the effectiveness of the changes aimed at stopping profits being artificially routed to "UK-linked tax havens".
Jersey, Guernsey, and the Isle of Man changed their tax laws in 2018 after pressure from the EU, and were subsequently kept off the bloc's so-called grey and blacklists.
But the report warns companies could still establish a "token" presence in the islands or simply shift profits to other "tax havens".
The effectiveness of the laws also depended on how stringently the rules were interpreted and applied by island governments, and how the EU reacted to their actions, the report states.
A requirement in Jersey to give authorities up to six years to assess whether a company is compliant may result in a "cat-and mouse game", Oxfam warned.
In response to the criticism, Guernsey's chief minister Gavin St Pier said the island had delivered "an effective and proportionate regime".
"Although rather predictably and sadly Oxfam - rather than concentrating on sorting out their own dire reputation and governance and instead of focussing on their core purpose - have found time to use their generous donors' funds to come out this week to criticise the regime's effectiveness, self-evidently, at this stage only three months into a new regime, without any evidence," he said.
The BBC has approached Oxfam for comment.
The European Parliament has had an urgent debate on the so-called Paradise Papers.
Commons Speaker John Bercow criticises the government for pulling a debate on greater tax transparency in the Crown dependencies - with ministers facing potential defeat.
BBC News Online
Chief ministers from Britain's Crown Dependencies are holding meetings in London on Monday morning in efforts to thwart transparency measures which could be forced on the islands.
On Friday, it emerged various amendments had been lodged to the UK's Financial Services Bill, being debated by MPs later.
They seek to force Jersey, Guernsey and the Isle of Man to make company ownership information of island firms public.
Campaigners said offshore leaks had shown anonymous companies were open to abuse.
The dependencies insist the move is unconstitutional and their private registers of company ownership are adequate.
One amendment lodged by Tory MP Andrew Mitchell and Labour's Margaret Hodge forces the islands to have publicly-accessible business registers.
Under the plans, they will be in place by the end of 2020 "for the purpose of the detection, investigation or prevention of money laundering".
Their amendment adds that the UK government must provide "all reasonable assistance" to the islands in setting the registers up.
It has the support of at least 40 MPs, including former Tory cabinet ministers Ken Clarke, David Davis and Sir Oliver Letwin, senior Labour backbenchers Margaret Beckett and Ed Miliband, and deputy Lib Dem leader Jo Swinson.
Ian Blackford, who leads the SNP group in Westminster, and Green Party MP Caroline Lucas have also put their name to the amendment.
The dependencies governments said they were "proactively engaging with the UK government and parliamentarians" to argue for rejecting the amendments.