Robert Gibson had his Labour Party membership terminated just days before he went missing.

The library campaigner left his home in Gipsy Hill before travelling to the Isle of Wight on June 13 last year and has not been seen since.

Four days before he disappeared, the Labour Party’s head office sent him a letter claiming he offered to stand as a Green Party member on social media in April.

Crystal Palace News has published the letter, signed by compliance officer for Labour Jane Shaw and dated June 9, 2016, with the permission of Mr Gibson’s wife.

It reads: “In April you posted on social media that you had offered to stand as a Green Party candidate in a local authority by-election and that you subscribed to the nomination paper of the individual who was later nominated to stand for election today for the Green against an official Labour candidate.

“You are therefore no longer a member of the Labour Party and have been removed from the national membership system. You will no longer be entitled to attend local Labour Party meetings.”

Officers from Hampshire Police searched a coastal path in the Isle of Wight that they were previously unable to wade through due to it being too overgrown.

Mr Gibson is described as white, 6ft, of slim build with grey/silver hair. He wears black rimmed Prada glasses.

He was last seen wearing a blue/grey T-shirt with green/brown khaki trousers.

Anyone with information on his whereabouts is asked to call Det Sgt John Stirling on 101, quoting 44160231297, or contact the charity Missing People on 116000.