A London airport has scrapped the 100ml liquid limit by using high-tech scanners which also allow electronics to be kept in hand luggage at security.
London City Airport has brought in technology which takes high-resolution 3D images of bags.
Travellers can now carry on up to two litres of liquid, and toiletries no longer have to be put in separate bags.
The UK Government has set a June 2024 deadline for most UK airports to install the machines.
Passengers at other airports, except Teesside which introduced new scanners in March, currently have to remove items such as tablets, laptops and liquids from hand luggage for security checks.
The current rules were introduced in November 2006, at the end of a ban on liquids in the cabin, when British police said they had foiled a plot to blow up as many as 10 planes using explosives hidden in drinks.
Trials
London City Airport started trialling the new technology more than a year ago and went live with four of the new X-ray machines, similar to CT scanners used in hospitals, on Tuesday.
Chief operating officer Alison Fitzgerald told the BBC that the screening staff had been retrained to use the technology, and the public can be assured it is safe.
"The level of processing now through the X-ray is even more secure than it was previously, and the machine has the ability to differentiate to between a non-dangerous and a dangerous liquid."
The machine would still reject images it was not happy with, she said, but it would allow staff to focus on potential threats while allowing items such as water, shampoo and perfume to go through.
It would also speed up the "door to gate" process.
Ms Fitzgerald added: "The whole process is quicker on the basis that previously you needed to empty your bag and put that in multiple trays whereas now it's one bag in one tray and you don't need to take everything out," she said.
Beginning of the end
Which? consumer expert Harry Kind said that, while it was the "beginning of the end" of a system introduced 17 years ago, people should not assume it was a rule change across the board.
"It's really important passengers actually check what the rules are for the airports they're flying from and flying to," he said.
But crucially it should reduce waiting times.
Many travellers reported delays of up to an hour at security, and in a recent survey 7% said they had missed a flight because of queues, Mr Kind added.