Sajid Javid has quietly abandoned plans to ban high-powered military-grade rifles after dozens of hard Brexit Conservatives and the DUP came together to voice opposition to the Home Office plan.

The police had wanted to ban .50- or higher-calibre weapons – which can immobilise a vehicle or truck from a mile away – and Labour was ready to support the government to get the ban through parliament despite the Tory rebellion.

But the home secretary has changed his mind amid the lobbying and on Friday put down an amendment to the offensive weapons bill going before the Commons next Wednesday, reversing the ban the government had proposed.

Louise Haigh, Labour’s shadow policing and crime minister, said: “Senior officers have warned the police have no known protection against these destructive weapons and yet ministers have still caved in to their restive backbenchers.”

Sixty-nine MPs had signed an amendment demanding a reversal of the ban, including Jacob Rees-Mogg, the chairman of the hard Brexit European Research group, as well as Steve Baker, Sir Bill Cash and Nadine Dorries.

ERG members were looking for the opportunity to stage a show of strength in parliament to demonstrate they also had the numbers to block Theresa May’s final deal Brexit deal when it comes to parliament in mid-December.

Royal Marines snipers firing a Barrett .50 calibre rifle. Photograph: Jon Mills/Rex/Shutterstock

Police forces support the ban on .50-calibre guns, which the National Crime Agency says have the power to immobilise a light or medium-size vehicle or truck at 1,800 metres and are too powerful to be used for sporting purposes.

Similar weapons were used by the IRA against British soldiers and members of the Royal Ulster Constabulary in the 1990s.

Mark Groothuis, the national firearms licensing liaison officer for counter-terrorism policing, had told MPs during the bill’s committee stages that he was concerned that “if one of these guns were to be stolen, again with the ammunition, and if it were to get into terrorist hands, it could be very difficult to fight against or to protect against”.

There are 129 rifles of .50-calibre held under licence in England and Wales, mainly to be fired on Ministry of Defence ranges in long-range shooting competitions. Critics of the proposed ban have said that no .50 weapon has been used in a crime in the UK since the IRA disarmed.

The ban was intended to apply to rifles with a power of “over 13,600 joules at the muzzle”. It was also opposed by the DUP, which is supposed to be supporting May’s government, and the Labour MP Kate Hoey.