A Marks and Spencer boss and former Tory frontbencher has criticised the government’s inflammatory language on immigration, warning that “the public is thirsting for a more civil discourse”.

Archie Norman, chairman of the retailer and an MP between 1997 and 2005, said Conservatives during his time in the shadow cabinet under William Hague “would never have used that language”.

Home secretary Suella Braverman claimed the UK was suffering an “invasion” over the numbers of migrants trying to reach the country.

It was followed on Friday by Home Office minister Chris Philp criticising the “cheek” of complaints from people arriving in the country “illegally” about processing centre conditions.

Appearing on Times Radio, Norman said under Hague “we would never have used that language, and the reason we didn’t is partly because it does mean that you trespass on very sensitive areas and you start appealing to people’s base emotions about race, about immigration, about people coming here from abroad”, and added: “I just think you have to be very careful.”

He continued: “I think one of things we saw with the Liz Truss episode, and probably with the Queen’s funeral, is the public is thirsting for a more civil sort of discourse, a more grown-up discourse.

“When you’re going into crisis, you really don’t want this partisanship. You want people willing to come together as a nation, as nations, and across the party divide.”

The comments come amid overcrowding chaos at the Manston holding centre in Kent, where at one point as many as 4,000 people were being detained for weeks in a site intended to hold 1,600 for a matter of days.

Meanwhile, immigration minister Robert Jenrick was heckled by some residents while visiting Dover with local MP Natalie Elphicke, while a woman in the town said her teenage son had been beaten up after she spoke out in the media over what has been happening.

Close to 40,000 migrants have arrived in the UK after crossing the Channel so far this year. But no crossings have been recorded by the Ministry of Defence over the last three days.