Hate crime spiked during parliamentary debates around what Boris Johnson labelled a “surrender bill” aiming to prevent a no-deal Brexit, police have revealed.

Senior officers would not be drawn on the specific impact of the prime minister’s language but repeated appeals for moderation from public figures.

The National Police Chiefs’ Council lead for operations said the increases “seemed to coincide with some of the debates” in parliament.

“Sometimes the way things are said can be perceived as giving permission to people to act beyond the normal boundaries ... it does have an impact on people,” Chief Constable Charlie Hall told a press briefing on Friday.

“We know some of that debate is quite strong but we ask people when those debates take place, that they are respectful and mindful of the impact that’s being had on others.”

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Mr Hall said the first hate-crime spike took place in the second week of September, which was when parliament passed the Benn Act shortly before it was prorogued for the first time.

Some far-right activists threatened to riot at protests over the introduction of the law and called MPs who supported it “traitors”.

Mr Johnson repeatedly described the law as a “surrender bill” or “surrender act” and the term was repeated by extremists, with high-profile figures including Tommy Robinson giving the prime minister their public support.

The second spike recorded by police was in the last week of September, which saw heated debates following the reopening of parliament after the Supreme Court ruled its suspension unlawful.

Mr Hall said hate crimes in September did not reach the levels seen immediately after the EU referendum in 2016, when a wave of xenophobic and racist incidents were reported across the country.

Another increase was seen around the original date for Brexit on 31 March this year, he added.

“It’s not necessarily what’s being debated but the nature of the debate – the way things are said,” Mr Hall explained. “We see that to some extent reflected in incidents reported across the rest of the country.”

Officials said the increases had been reported by regional police forces across England and Wales through intelligence reports, but that no statistics for last month could yet be released because of recording processes.

Boris Johnson defends his language in the house of commons

Several MPs have appealed for the prime minister to moderate his language and said they were experiencing an increase in personal abuse.

Mr Johnson has defended his speeches and called suggestions of a link to threats to the safety of MPs “humbug”.

Cross-party MPs have reported a dramatic increase in abuse since the EU referendum and several people have been prosecuted for making threats to politicians.

Mr Hall said reports of abuse towards MPs also spiked in September and more have been taking up the offer of security advice from the police Parliamentary Liaison and Investigation Team.

“Nobody, including MPs, should expect to experience abuse and harassment, nor their families or staff,” he added.

Police are also bracing for an increase in protests around 31 October but said there was “no intelligence at the current time” indicating that they could be violent.

Plans put in place earlier this year mean up to 10,000 officers will be available to respond to unrest, either around demonstrations or potential delays at ports and shortages of food, petrol, medicine and other supplies.

Mr Hall said leaders had planned for the “reasonable worst-case scenario” but were not predicting that it would happen.

Police said they still do not know what legal powers and frameworks they will be left with on 31 October because a deal with the EU has not been finalised.

Deputy assistant commissioner Richard Martin, the national lead for Brexit preparations, said that if no deal is reached the UK will be kicked out of all EU law-enforcement mechanisms and databases at 11pm on Brexit day.

Boris Johnson has been accused of worsening the abuse of MPs (Getty)

He said the alternative tools that officers would have to fall back on are “not as efficient” and will incur an estimated cost of £26m a year through extra staffing and working hours because of “manually doing things using slower routes”.

Mr Hall said Brexit would cause a “stretch” on wider policing if officers are taken out of their normal roles or sent to ports in Kent and Hampshire, where local forces have requested assistance.

At least 26 police forces have already imposed leave restrictions on their officers in October and November.

Police are concerned that the loss of powers including the European Arrest Warrant and access to the Schengen Information System database will reduce their ability to detain foreign criminals or extradite those wanted by EU countries.

An alternative system of Interpol “red notices” does not give officers the legal power to arrest a wanted person on sight, meaning they must be let free until a court warrant can be obtained.

“We could end up with the unenviable position where an officer has a person in front of them, someone wanted for burglary in France or something, and they can’t arrest them,” Mr Martin said. “That’s our main risk.”

He said that the Home Office had drafted emergency legislation extending powers under Interpol red notices but it has not yet been passed “because of parliamentary time”.

“We are ready to use alternative arrangements to the current EU tools and powers, but they are not like-for-like replacements. In all cases the replacements are slower, less effective and more bureaucratic for officers than our existing setup,” Mr Martin said.

“Existing EU tools allow us to respond quickly and intelligently to crime and terrorism impacting the UK and the EU – they make us better at protecting the public. We want to avoid leaving without a deal because that would see us lose access to those important tools.”

A Home Office spokesperson said: “We are working closely with policing, operational partners and with EU member states to ensure we are ready when we leave, whatever the circumstances.