Health officials fear Britons are starting to get complacent about the Covid-19 lockdown after traffic and mobile phone data revealed more of us are on the roads and looking for directions.

Professor Stephen Powis, national medical director of NHS England, said on Saturday “there was a little bit of concern” after the unseasonably warm weather drew big crowds to public spaces.

The Metropolitan Police sent officers on bikes to keep an eye on London’s Hyde Park, while North Yorkshire Police revealed 50% of shutdown fines issued so far have gone to tourists visiting beauty spots in the area.

Elsewhere, B&Q’s decision to reopen 130 stores saw massive queues forming outside its outlets in Bristol and in Swansea, as the public use the shutdown to catch up on DIY.

At the Downing Street briefing, Prof Powis said traffic levels are down 59% compared to February, but grew by three percentage points in the last seven days compared to the previous week.

Mobility data released by Apple revealed that despite a dramatic drop in requests for directions, in recent days searches for maps for walking or driving have increased by eight percentage points.

Prof Powis said: “It won’t take much for this virus to start increasing its transmission again and to spread more widely.”

He added: “It would be foolish and not right if we lost the benefits that we have gained over the last four weeks, which I know have been hard for everybody.

“So it’s really important that despite the weather, we stay at home, we keep to the guidelines that we’ve been issued with.”

The Metropolitan Police Federation (MPF), a body representing Met officers, said despite its assertions to the contrary, the Government was sending out mixed messages around the shutdown.

MPF chairman Ken Marsh questioned the wisdom of allowing DIY stores to reopen.

Mr Marsh said: “Police officers are on the front line of combating the coronavirus crisis.

“We need clear and unambiguous laws, guidance and communication from the Government around what the public can and can’t do. What is essential and what isn’t.

“If officers are confused about all this then so will the public be.”

Various forces have highlighted the most flagrant breaches of the guidance they have come across on social media.

Devon and Cornwall Police fined a couple from Kent for driving around 300 miles for a “mini-break” by the sea.

Their car was confiscated after the driver was found to have no licence or insurance.

In Gwent, officers described it is “unacceptable” that people drove nearly 12 miles from Newport to the blue lagoon at Pantygasseg.

Police in Gloucestershire issued warning letters to three people in Paganhill after holding a party at one of their houses.

And a pub in Pendeford, Wolverampton, had its licence suspended for three weeks for secretly serving alcohol.