Traffic data showed jams increasing inside London and its surrounds, and train prices were surging with increased demand.
Additionally, train tickets were selling out quickly. By 7pm on Saturday evening, there were no trains available online from several London stations including Paddington, Kings Cross and Euston.
Footage taken at London’s St Pancras station showed passengers streaming down the concourse to board trains heading north.
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.
Harriet Clugston, a passenger, 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 [bags] on seats but being asked to remove them by other passengers as the train is so full.”
One 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 Press Association.
Anectdotal reports suggested motorways leaving London were packed with drivers heading out to beat the new restrictions.
Some people were driving to leave their newly-restrictive areas for a long stretch of time, while others were leaving to spend the last few hours without tier 4 anywhere.
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 told Press Association.
Boris Johnson announced on Saturday that all areas of east and southeast England – including London – that had been in tier 3 would go into the newly defined tier 4 from midnight.
Tier 4 effectively returns residents to the rules in place during the national lockdown.
Those in tiers 1, 2, and 3 are now only able to mix with other households for a Christmas celebration on 25 December instead of the longer stretch initially planned by the government.
Additional reporting by Press Association