Tributes have been paid to the Open Britain press chief who was among six people killed in a seaplane crash near Sydney on New Year’s Eve.

Will Cousins, head of press at the pro-EU campaign group, was praised as a “great team player” who had quickly mastered skills that “elude many for their entire careers”.

The 25-year-old was killed when the seaplane in which he and several family members were travelling plunged into a river 30 miles north of Sydney.

He died alongside his brother, Edward, 23, father, Richard, 58, chief executive of catering giant Compass, and the older man’s fiancée, magazine editor Emma Bowden, 48, her 11-year-old daughter Heather, the BBC reported.

Gareth Morgan, the Australian pilot, was also killed.

Today colleagues paid tribute to Cousins, who was known as a confident, professional and courteous campaigner as he dealt with journalists from across the political spectrum, including from LabourList.

“All of us at Open Britain are devastated by the tragic loss of Will and his family”, said Open Britain chair and public relations tycoon Roland Rudd.

“Will was an extraordinary young man who was passionate about what he did; who took deep pride in his work; and came into the office every day with enthusiasm, energy and determination.

“Will saw his role at Open Britain as more than a job. For him, it was a cause akin to a crusade to stop Britain crashing out of the EU with no deal or a bad deal.

“Will was a great team player who loved the camaraderie of our young team and developed close relationships with all his colleagues. He will be missed beyond words.”

James McGrory, executive director of Open Britain, said: “The dreadful news about Will and his family has left all of us at Open Britain in shock and deep sorrow.

“Will was one of the most impressive people you could ever work with. His ability, dedication and passion were an inspiration to everyone around him. At such a young age, he had mastered skills that elude many for their entire careers.

“We have not just lost a special colleague but a wonderful friend. Will’s razor-sharp wit, easy company and generosity will be missed even more than his huge brain, peerless prose and fearless ideas.

“Words cannot express how much I and the rest of the team at Open Britain will miss Will. We have lost a brilliant colleague and a true friend.”