One of the first Gaza flotilla activists to return to Britain has said she “can’t remember what happened first” when Israeli commandos boarded her boat, but described “hearing bullets flying”.

Sarah Colborne, the Palestine Solidarity Campaign’s director of campaigns, described the scenes as Israeli commandos boarded the Mavi Marmara ship which was leading the flotilla.

Speaking at a press conference after arriving back in London she said: “I saw four dead bodies laid out on the floor. As we were moved out we were cuffed and our telephones and cameras were removed. We had to sit or kneel in lines on the deck.”

Ms Colborne said she had seen one activist shot in the head during the incident on Monday.

Amid allegations in The Times of links between Islamic extremists and the Turkish charity which had 40 members on the ship, Ms Colborne said she and others on board had not been exploited by such organisations.

“There is nothing extremist about carrying out what the UN has asked us to do. What we were doing was taking aid, concrete, medical equipment.”

Asked about Israel’s allegations that the activists used weapons and heavily resisted the IDF officers, Ms Colborne denied the Israelis had been physically attacked.

She said: “All the passengers and boats went through security checks before leaving Turkey. We had kitchen knives because we were there for some days and needed them to cook. I did not see any kitchen knives used [against the Israelis].

“I saw people trying to stand there and stop the Israelis getting on the boat. We had no arms whatsoever.”

She said she did not know if poles had been used by the activists but appeared confused about her position on the boat and from which deck she had witnessed events.

Bullets had been “flying around all over the place”, but Ms Colborne said the activists had not shot at Israelis, they had only been acting “very aggressively”.

“I did not see any guns being taken off Israelis and used against them.”

She claimed some Britons had been denied access to consular services after reaching the Israeli port of Ashdod, and later at Be’er Sheva prison.

Still wearing her Israeli prison uniform, Ms Colborne said: “it was terrifying. I’m in a very fortunate position to be here. I hope the horrific deaths will not be in vain and will be a wake up call to the world.

“This was an attempt by Israeli to stop humanitarian aid getting to Gaza. We will continue to challenge the blockade and work to end the siege.”