Protestors from the Viva Palestina convoy, supported by MP George Galloway have clashed with Egyptian security forces on the Gaza border.
Several police officers and protestors were injured and seven activists were arrested but later released.
Alexandra Lort-Phillips, 37, who was part of the convoy, said: "I have 42 people in my team.
"Out of those three Britons have been injured. There are head injuries, cuts.
"We started getting pelted with stones by people in plain clothes, then the police started moving in, using tear gas and batons. People were quite severely beaten."
More than 500 supporters in 198 trucks carrying aid supplies drove the convoy to Rafah, on the border with Gaza but a quarter of the trucks were denied entry. Those allowed in were allowed 48 hours in Gaza to distribute their aid.
The rest of the convoy is now in El-Arish, the Egyptian port on the Gaza border. They were told to pass into southern Israel and cross the controlled border there
Mr Galloway said he thought the order by the Egyptians was unacceptable: "We refused this.
“It is completely unconscionable that 25 per cent of our convoy should go to Israel and never arrive in Gaza.
Because nothing that ever goes to Israel, ever arrives in Gaza.
“This is a dictatorship funded by the United States and Israel who are stopped aid getting into Gaza. The people who fought back last night would be hailed as heroes if this was happening in some other countries, like Burma.”