A top Home Office civil servant has said that the use of troops on Britain’s borders could be a "last resort” in the event of the UK crashing out of the EU without a deal.

Appearing on the Home Affairs Select Committee, Philip Rutnman, the Home Office permanent secretary, was quizzed on whether the UK had a sufficient number of border force staff in place to deal with a range of scenarios at the end of the Brexit negotiations.

Asked by Yvette Cooper, the chair of the committee, whether the UK could end up relying on the armed forces in order to provide border checks in the event of no deal, Mr Rutnman replied: “I think it would be unwise to rule anything out. It seems clear to me that any use of the military would be an absolute last resort.

“Our preference – strong preference – is to deal with the border and security needed at the border through border force and that is the basis in which our planning is proceeding.”

Mr Rutnman added that the Home Office is already in the process of recruiting an additional 300 border forces officers, to “ensure we can deal with the consequences of leaving the European Union with a deal or without a deal”.

But his comments were seized upon by James McGrory, the executive director of Open Britain, who told The Independent that the spectre of troops patrolling the UK border “shows just how absurd and damaging the Government’s threat to leave the EU with no deal is”.

He continued: “In Northern Ireland in particular, such an action would be an appalling regression to the border of the past that ministers keep promising to avoid.

“And after years of defence cuts, it’s not like we can spare large numbers of soldiers to perform functions that are properly the preserve of the police and border force.

“A Brexit with no deal would be damaging and unworkable, with consequences that we cannot foresee. It is time their Government dropped this threat and negotiated to retain a close relationship with Europe that keeps Britain an open, tolerant and peaceful country.”

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During her two-hour grilling in front of the committee Amber Rudd, who appeared alongside Mr Rutnman, said it would be “unthinkable” for the negotiations with Brussels to end without a deal in place.