Four British tourists seriously injured in the Tunisian beach attack have been flown back to the UK by the RAF.
It is feared that about 30 UK citizens were killed, though only 18 have so far been confirmed among the dead.
The government says all those hurt at the resort near Sousse on Friday will be brought home in the coming hours.
Tunisian authorities have arrested several people on suspicion of helping the gunman, who had links to the jihadist group Islamic State.
A team of British consular staff was on the ground in Tunisia within hours of the attack, and is currently helping victims and their families.
The four injured Britons returned on a specially modified RAF C17 transport plane which left Brize Norton in Oxfordshire for Tunisia on Monday afternoon. Medics experienced at bringing injured service personnel back from operations overseas were on board.
The Ministry of Defence said the plane flew into Birmingham airport, where one of the patients was taken off, before it continued to Brize Norton.
The MoD said it was working with NHS England to arrange “patients’ onward moves once they’re back in the UK to take each person to the best hospital in their area for their needs”.
Foreign Secretary Philip Hammond is to chair a meeting of the government’s Cobra emergency committee.
Meanwhile, a major exercise to test how British police and security services would respond to a terrorist attack begins in central London.
Scotland Yard is stressing that the two-day training drill had been planned in the wake of the Charlie Hebdo magazine murders in Paris in January and is not in response to any new threat.
Tunisia beach attack: The victims
The names of those killed in the attack are slowly emerging. Here’s what we know so far about those who lost their lives, as well as those who are injured and missing.
Some survivors have also been speaking out about their ordeal
A national minute’s silence will take place on Friday at 12:00 BST, a week after the shooting.
Every primary and secondary school in England is also starting to receive guidance on how to spot grooming of pupils by extremists.
The document forms part of the government’s Prevent counter-terrorism strategy and follows concerns over potential radicalisation of teenagers, but is not a response to the Tunisia attack.
In a speech to the Commons on Monday, following a minute’s silence held by MPs, Prime Minister David Cameron described the attack as “brutal and sickening”.
Earlier, Home Secretary Theresa May laid flowers on the beach near Sousse where gunman Seifeddine Rezgui shot at people near the Imperial Marhaba and Bellevue hotels.
Mrs May held talks with the Tunisian, German, French and Belgian interior ministers on addressing the threat from IS.
The Tunisian authorities have said they believe the 23-year-old student had help with the attack, and one of those detained is reported to be Mr Rezgui’s flatmate, according to local media.