Passengers faced packed train carriages out of London as many attempted to flee the capital following the announcement of tougher coronavirus restrictions.

Travellers were told that social distancing “will not be possible” due to the volume of people on board, and those that felt “uncomfortable” should not stay on the train.

It comes after Boris Johnson made the shock announcement that large parts of eastern and south-east England, including London, would be placed under Tier 4 restrictions.

Tier 4 – which is the highest possible level in England – effectively returns residents to the rules in place during the national lockdown.

Mr Johnson told a Downing Street press conference at 4pm on Saturday that the rules would come into effect at midnight.

By 7pm on Saturday evening, there were no trains available online from several London stations including Paddington, Kings Cross and Euston.

Footage online showed large crowds at St Pancras station waiting to board trains to Leeds.

Harriet Clugston said that people on board the trains had attempted to secure space for themselves, but that there was not enough room to do so.

“As expected, train is crammed,” she wrote on Twitter.

“Announcement on Tannoy says social distancing ‘will not be possible’ due to volume and to get off if you are not comfortable with that.

“People have tried to secure social distance by placing on seats but being asked to remove them by other passengers as the train is so full.”

Another woman, who did not wish to be named, said she and her partner had made the “split decision” to take their young son to her parents’ home on the coast.

“We just made the decision to leave based on the fact that my parents said come, and we couldn’t bear the thought of no fresh air and a toddler going rogue round a small flat for the foreseeable,” she told the PA new agency.

“We also really just felt we wanted to get the baby somewhere a bit safer with a garden, though we know a lot of people won’t have that luxury.

She added: “The grandparents are just desperately happy they’ll see their grandson.

“We obviously worry about taking something down to them, but they seem happy to take the risk.”

Izzy, 22, from Bristol, said that she wanted “the security of being home for Christmas” and that her parents had come to collect her before the restrictions came into effect.

“I have a slight nervousness that they might block the roads or something stopping me going home,” she said.

“I’m moving out of my flat so I need my dad to come and get me and he feels more comfortable doing it before Tier 4 kicks in.”