Immigration specialists have criticised the home secretary for suggesting that thousands of people of the so-called 'Windrush generation', fearful about their immigration status, do not need to instruct solicitors.

An escalating row about Commonwealth immigrants who arrived as British subjects, given settlement rights under the 1971 Commonwealth Immigration Act but now threatened with deportation because they cannot prove their status, has prompted calls for Amber Rudd to resign.

Rudd has established a taskforce to help people of the Windrush generation establish their rights. A helpline was set up to enable people to contact the Home Office.

In a Commons debate on Monday, Rudd said she had listened to some of the calls to the taskforce and said the way in which callers were engaging with the border people helping them had been 'very constructive'. She said: 'They do not need to have lawyers. In this process we have put in place, there will be no need for lawyers to engage.'

Chai Patel, legal and policy director at the Joint Council for the Welfare of Immigrants, said Rudd was 'grossly irresponsible' for advising people against seeking independent legal advice before calling the Windrush helpline.

Patel said: 'Her [department] is in a state of constant catastrophe when it comes to decision making, with over 50% of appeals against its decisions successful. In these cases, there isn’t even an appeal route. Nor is there any written guidance as to the scope and procedures under which this special taskforce will operate. We would certainly recommend that people contact our free helpline for undocumented migrants before calling the helpline.'

Philip Trott, a partner in the immigration department at London firm Bates Wells Braithwaite, said: 'However simple the process proposed by the minister, as with all applications made to the Home Office, evidence supporting them is key and applicants are not merely able to make an assertion of fact. Inevitably there will be some testing of the application especially in relation to family members born here to Windrush generation members. The Home Office's track record will justify rightful cynicism by those that understand the system.'

Wesley Gryk, senior partner at London firm Wesley Gryk Solicitors, said his firm's experience shows the Home Office does not always get the law right in its decision-making.

Gryk said: 'It is therefore over-optimistic to think that they will be able to deal with everyone’s applications correctly, when these often involve complex historic points of British nationality law and immigration control. The Home Office does appear to be offering a personalised service for these people but it can’t be trusted to be able to handle complex cases well and so these people, who are often elderly and more vulnerable (which is often why they have not been documented previously), may well still need legal support through the process.'