Israeli authorities boarded a British yacht, took down its flag and "almost strip searched" its crew as they attempted to break the blockade to Gaza, a Briton on board has said.
Vish Vishvanath was one of nine people travelling on the British-flagged catamaran Irene when it was intercepted.
The freelance photo-journalist from Twickenham, south west London, said the vessel had been "hijacked" in international waters and surrounded by about eight boats whose crew trained machine guns on them.
The armed Israeli authorities who came on board took down the boat's British flag, he said, "which is something you're not supposed to do".
The 36-year-old was one of two Britons on board the yacht. The other was Irene's captain, Glyn Secker.
Both men were detained in Israel prior to deportation.
Arriving at Luton Airport on Wednesday morning, Mr Vishvanath said he had been "almost strip-searched" and that the Israeli authorities had confiscated all his camera gear and his phone.
The group set sail earlier this week from Turkish-controlled Northern Cyprus, with a consignment of medicines, toys and water purifiers.
But the catamaran was seized on Tuesday around 20 miles from Gaza by Israeli naval forces, with nine people and aid for the territory on board.
One of two former Israeli Defence Forces members on board Irene repeatedly read out a statement telling the naval forces that "the occupation is illegal", Mr Vishvanath said.