Theresa May's attempt to address the Windrush crisis broke down on Thursday after the former head of the civil service described the hostile environment towards immigrants under May's time as home secretary as 'almost reminiscent of Nazi Germany'.

Lord Kerslake, who has been advising Jeremy Corbyn, gave an interview to BBC Newsnight and called for a full investigation after the prime minister claimed the decision to destroy thousands of landing cards for Commonwealth immigrants was made in 2009 under a Labour government.

Labour denies this and said the Home Office had previously admitted the decision was made under May in 2010.

It came as church leaders across the UK condemned the government's handling of thousands of people from around the Commonwealth came to the UK after the Second World War to fill a labour shortage. The 1971 Immigration Act ended the free movement between Commonwealth nations that had existed until that point but gave all Commonwealth citizens living in the UK the right to remain. However the Home Office did not keep a record of those given leave to remain meaning they now find themselves having to prove they are here legally without having the paperwork to do so.

Bishop Paul McAleenan, head of the UK Catholic Church's migration policy, welcomed May's apology to the Windrush generation but said their treatment was 'extraordinary and unacceptable'.

'To deny them access to the benefits of the state they have served so well would have been truly reprehensible,' he said.

'The Windrush generation and all communities that have made meaningful contribution to this country deserve to be treated fairly and with respect.'

Rev Dr Michael Jagessar of the United Reformed Church said the predicament for Windrush residents 'boggles the mind'.

'Consider the incompetence, the Home Office did not keep a record of those granted leave to remain or issue any paperwork to confirm it. So how can the individuals now prove they are in the UK legally? Furthermore, why should the onus be on them to prove they have the right to remain? Would any of this apply to Australian, Canadian, South African, Indian or Pakistan-born citizens facing the same problem?

'It was the British government who invited the Windrush Generation to Britain to help rebuild our country in the wake of the Second World War,' he added.

'But now the Windrush children must seek legal advice, provide proof and incur expenses to prove they have the right to be in this place they call home and where they have contributed so much over many years. It is shameful that these individuals continue to be treated with such contempt, disrespect and lack of dignity.'

Meanwhile a number of Church of England bishops also spoke out, urging their parishes to back a petition that demanded amnesty for the Windrush generation.

The issue dominated prime mInister's questions on Wednesday after May attempted to get an advantage over Corbyn with the surprise claim the decision to destroy landing cards had been made in 2009.

It later emerged two decisions had been made, one in in June 2009 and one in October 2010 and both were made by officials with the UK Border Agency, rather than by ministers.