The “mish-mash” of “completely unclear” new guidance and “confusing messages” from Government is a “recipe for disaster” for police officers tasked with enforcing the lockdown, according to a lawyer.

Raj Chada, head of the criminal defence department and a partner at firm Hodge Jones & Allen, made the comments as he warned of the problems which having different rules for separate parts of the country could cause as the Government unveiled changes to restrictions in England.

Previously some concerns have been raised about police misinterpreting lockdown rules or being overzealous in their approach, incorrectly issuing fines and prosecutions being carried out under the wrong legislation.

Mr Chada told the PA news agency: “We may find even more the problems which we have seen with Covid legislation to date” and that cases could “fall apart” at court if challenged by a member of the public who feels they have been wrongly reprimanded.

It is really hard to see how police officers can pursue effective enforcement for the next few days while there is so little clarity

He also questioned whether the legislation complied with human rights laws, because there was “no certainty” and the public should know what constitutes an offence, adding: “There has to be some certainty to it.”

The College of Policing said fresh guidance for officers on changes to the rules would be issued “later this week”, although it is unclear if this will be before the new legislation comes into force.

Mr Chada said all of the information should have been finalised to be provided at the same time, adding: “Again it means confusion and again it will mean challenges.

“It’s nonsense, it’s just a load of nonsense and they have messed it up.”

Yvette Cooper, chairman of the Commons Home Affairs Committee, said the lack of clarity will make the job for police “much, much harder”, adding: “It is really hard to see how police officers can pursue effective enforcement for the next few days while there is so little clarity.”

She said she was “particularly concerned” at the increase in fines, adding: “Mistakes will be made on both sides as regulations change.

“The Government should first ensure that enforcement can be accurately and effectively done.”

Meanwhile, John Apter, the national chairman of the Police Federation of England and Wales, which represents rank-and-file police officers, told PA: “We need unambiguous clarification of what this means for us and the public.

“There is a desperate need for crystal clear clarity on what is and isn’t allowed.”

He said he does not “understand at all why the fines have been increased” in England when officers are encouraged to police by consent and issue fixed penalty notices as a last resort.

There was “increasing frustration” from officers that their hands are tied and they were now being expected to “pick the bones” of what is unlawful and what is not, he added.

Earlier his counterpart Brian Booth, the chairman of the West Yorkshire Police Federation, said the relaxation of restrictions had set officers an “impossible task” and the new rules were “effectively unenforceable”.

Andrew Slattery, assistant chief constable of Cumbria Police, told PA: “Police officers are already in a very difficult position.

“The job for police officers has been very difficult from the outset.

“We do expect to have a very difficult weekend.”

Addressing the House of Commons on Monday afternoon, Boris Johnson said he had “huge admiration” for the way that the police have enforced the rules so far and urged the public to “apply their common sense in the application of those rules.”

His spokesman said police would be advised to use continued “discretion” when enforcing the new measures, adding: “I would say, give the public credit for the fact they have followed the advice so far and there is no reason to think they won’t do the same as we move into this next phase.”

But Kirsty Brimelow QC, a barrister at Doughty Street Chambers, told PA: “There is plenty of evidence that the police have not understood their powers to date and we have seen many unlawful convictions over weeks.

“The vast disparity in the number of fines issued, according to police force, must in itself raise concern.

“The Government should be recommending a review of all fines so far issued rather than continuing deeper into this enforcement mess.

“The police have even less chance of getting it right with wider and vaguer laws subject to multiple interpretations.”