The government needs to “get its act together” to prevent panic-buying and civil unrest over Brexit, officials have warned.

A group coordinating contingency planning in London heard that with 44 days until Britain is due to leave the EU, authorities still have “no direct indication of what we’re planning for”.

Suggestions that the government may delay Article 50 remain unconfirmed, and no date has been set for a parliamentary vote on a deal with the EU since Theresa May’s proposals were rejected last month.

Fiona Twycross, chair of the London Resilience Forum, said people would stockpile food, fuel and other supplies because of the uncertainty.

“The government might tell people not do it but as soon as they can give people some certainty the better,” she told the London Assembly EU Exit Working Group.

Britain Before Brexit: Greater London Show all 16 1 /16 Britain Before Brexit: Greater London Britain Before Brexit: Greater London West Croydon A police van’s speed and siren bring people to shop windows, keen to watch the drama of the public space, curious to know if a crime has been committed and lining up like townsfolk in a western movie Richard Morgan/The Independent Britain Before Brexit: Greater London Trafalgar Square Morning light illuminates a typical scene outside the National Gallery. Everyone interacts with a phone, held in hands and gazed at, or held in the hands of others and posed for. The figure in the background is on another level, an exception, an anomaly Richard Morgan/The Independent Britain Before Brexit: Greater London East Croydon A dispute about shoplifting outside a store’s entrance, conducted in French, revolving around a gold watch Richard Morgan/The Independent Britain Before Brexit: Greater London Bank The Chinese flag hangs over the centre of British finance, its red blush bringing luck to the morning. St Paul’s Cathedral occupies the blue distance Richard Morgan/The Independent Britain Before Brexit: Greater London Bond Street Three pairs of legs and feet in different states, playing different roles in the heart of British commerce: one clothed, striding purposefully; another of white plastic, made to model and convince; the last barefoot, not standing Richard Morgan/The Independent Britain Before Brexit: Greater London Upton Park Plastic bags dress naked trees, only partially, flaying in the wind, torn and damp, leaving most of the branches exposed, like black cracks spreading across thin ice, across the tower block of civilisation Richard Morgan/The Independent Britain Before Brexit: Greater London Westminster A pro-Brexit protester walks past the Houses of Parliament and the anti-Brexit protesters camped opposite. Both have appropriated the Union Jack, claim to be acting in the national interest and to be patriotic. Caught in between are child and mother, who photographs the ‘home of democracy’, or herself Richard Morgan/The Independent Britain Before Brexit: Greater London Islington A new tube map is put up outside the station, hands reaching high, stretching upwards, as if in worship of the security camera, in awe of surveillance itself, one of London’s most valued currencies Richard Morgan/The Independent Britain Before Brexit: Greater London Tooting Broadway A huge bingo hall hidden away from the high street, populated sparsely by a few players. There’s so much concentration and focus. I can’t decide if they’re there to play, to win, to hide, to escape, or to kill time Richard Morgan/The Independent Britain Before Brexit: Greater London The Mall Horses are tourist attractions in certain parts of London, especially when they’re dressed in military regal attire and carrying a soldier or a guard. Tourists pose alongside them for selfies and generic holiday snaps, which when taken daily in their millions, re-enforce a global image of London as a hub of ceremonial pomp and ritual Richard Morgan/The Independent Britain Before Brexit: Greater London Tooting Bec An anonymous critique of an advert’s imagery, wheeling out the age-old distinction between lust and love, sex and companionship, surface and interior, shallowness and depth, superficial and real Richard Morgan/The Independent Britain Before Brexit: Greater London Wandsworth A declaration of the existence of community is damaged and broken. A sign portraying strength and solidarity looks weak and sad and lonely when it begins to crumble and fall apart Richard Morgan/The Independent Britain Before Brexit: Greater London Buckingham Palace I watch a lineup of paparazzi photographers outside the palace. They wait to pounce upon blacked out windows concealing guests to the Queen’s Christmas lunch. They appear bored and unenthusiastic, as if photography were for them but a chore that flashes light on celebrity faces Richard Morgan/The Independent Britain Before Brexit: Greater London St Paul’s The city is reflected by its values: a relentless list of imperative commands to become something else, some better version, upgraded; a message that says we need to acquire to improve; a hard-hitting reminder of your inadequacy and incompleteness Richard Morgan/The Independent Britain Before Brexit: Greater London Colliers Wood A laundrette on the peripheries, zone 3, where a man sits below another London – Piccadilly Circus – with its giddy movements and interactions, its colours and vibrancy, where life is shaken up and spun, as if in one of the washing machines below, rotating and loud, everything inside blurred Richard Morgan/The Independent Britain Before Brexit: Greater London Uxbridge A building site concealed with an image of what will be. A common way to cover up the messy process of (de)construction. The housing development claims to be affecting time and space, moving people into new places and better futures, fundamentally altering their existence Richard Morgan/The Independent

“This is an issue government needs to sort out, they need to get their act together so that people don’t take what in some instances could be seen to be a very rational decision.”

Dr Twycross warned that if stockpiling turns into panic-buying, poorer households and vulnerable people would be more exposed to any resulting shortages.

John Hetherington, City Hall’s head of London resilience, said public behaviour could also drive a fuel crisis, potentially sparking traffic gridlock and civil unrest.

“The hardest-hit area would be the southeast of England, where there could be very localised shortages that are then exacerbated by public behaviour,” he added.

Mr Hetherington said authorities and businesses may have to adapt to a “new normal” but that much depended on the public’s reaction and EU decisions on supply routes.

He added that the uncertainty was “not necessarily the fault of the civil servants we work with. I think we are exasperated as we are.”

Authorities in London are working to mitigate risks around potential protests and disruption to borders and food, energy and food supplies.

Brexit: Theresa May dismisses claims she plans to extend Article 50 as something “overheard in a bar”

But Dr Twycross said that the “chaotic situation” in the government meant authorities have little information on what to prepare for and are making “educated assessments”.

“If we’re not going to get additional detail until there is a parliamentary conclusion that presents a big risk,” she told the London Assembly EU Exit Working Group.

Dr Twycross said instructions from government had only been modified “very slightly” since technical notices were sent out last year, despite a dramatic shift towards no deal.

“My concern is that in some other [local authority] areas, people have been waiting until they get a stronger indication from government,” she added.

“They took as read that the government was confident that there would be a deal, and now it’s getting too late, and everyone is having to play catch-up.”

Dr Twycross, a Labour assembly member, said some officials had feared speaking openly of risks around Brexit because they feared “entering a political arena”.

A representative of the NHS London coordination centre said that six weeks of medicine and equipment reserves had been built up nationally to mitigate any supply issues around Brexit.

He said no “immediate impact” on the NHS workforce was expected.

Working group chair Len Duvall concluded: “We are planning for the worst case scenario but whatever happens in 44 days’ time is going to be chaotic.”

A Ministry of Housing, Communities and Local Government spokesperson said: “MHCLG is committed to working with local government and local leaders to ensure they are adequately prepared to respond to any Brexit scenario. The government remains confident that it will secure a good deal with the EU. Nevertheless, it’s only responsible to prepare for a number of scenarios.