A former Conservative Cabinet minister was castigated after his reference to a “human tide” of asylum seekers from central Europe arriving in Dover, secret letters show.

Sir Brian Mawhinney was criticised by Mike O’Brien, the immigration minister, for his language and urged to use “measured words” instead.

The letters between the two, in October 1997, were released by the National Archives, Kew.

In his letter, concerning “gypsies arriving at Dover”, Sir Brian, who was then shadow home secretary, wrote: “Thank you … for setting out the reasons why the Government appears to be taking no comprehensive action to stop this human tide.

“Clearly, the government is not gripping this crisis under existing arrangements.

“So in order that we should have openness and clarity, and the people of Kent can have appropriate protection of their local services, I am asking you immediately to impose visa requirements on all Czech and Slovak citizens.

“In that way the problem can be stemmed and then resolved.”

Mr O’Brien said the situation in Dover was “difficult, and in some respects, tense”, adding that the return of asylum seekers to Europe was “complex”.

He said: “I am sure you will agree that inflammatory comment would only make the situation worse and that measured words are important.

“Your letter refers to a ‘human tide’, and I trust this would only be used in a private context.”

He said Conservative claims about the numbers of migrants arriving in Kent were described by police as “unsubstantiated”.

Migration on the south coast remains a political issue, particularly during election campaigns.

Sir Brian, who served as Tory Party chairman from 1995 to 1997 under Sir John Major’s government, died in November 2019.

He served as minister of state for the Department of Health and secretary of state for Transport, and was Football League chairman for seven years from 2003.