A 54-year-old man from High Wycombe who was confronted by paedophile hunters when he arrived at a railway station was convicted on Friday of attempting to meet a child following sexual grooming.

Mark Porter, now 55, who lives near the town centre, thought he would be greeted by a 14-year-old virgin called Jenny, but instead was caught in a sting operation by campaigners Neil and Katie Ivall.

The jury at Luton crown court found Porter guilty by a majority 11 to 1 verdict. He was bailed by Judge Philip Bartle QC, who will sentence him once reports have been prepared.

Prosecutor Will Noble told Luton crown court the Ivalls, from Dunstable, run a non-profit organisation called 'Chris Fear' after a member of Katie's family was groomed over the Internet by a paedophile.

He said Katie had been contacted by a man who claimed his 11-year-old daughter had been contacted by Porter through the Internet.

As a result she set up a fake Facebook account using the name Jenny Johnson. She stated she was 14 and posted pictures of a girl.

Mr Noble said: "The Ivalls found the defendant's details on Facebook and, posing as Jenny, clicked 'Like' on one of the defendant's photographs and waited to see what would happen."

After 22 January this year there were a series of online conversations, all of which were recorded.

"The defendant repeatedly sends flattering messages complimenting Jenny, offering to take her to Thorpe Park and promising her gifts and treats. He asks for pictures of Jenny as the conversations become more sexual." said Mr Noble.

In the first of three phone conversations, that were secretly recorded, Mr Noble said the defendant tried to persuade Jenny to come to his flat in Buckinghamshire.

In one he said if Jenny's mother found out she'd hit the roof. He said: "I would be registered as a f.......paedo."

He a told her he would not pressurise her.

Mr Noble said that they arranged to meet at 8pm on Friday March 25 outside Luton rail station saying: "Little did he know it was a set up. Mr and Mrs Ivall were laying in wait for Mr Porter at Luton train station and , with the help of others, they detained Mr Porter and called the police."

He said the defendant tried to drive away, but his path was blocked. While they waited for the police he was seen "desperately" deleting pictures and online conversations from his mobile.

When he was arrested Mr Porter told officers: "Before we start I had no intention of having sex with an underage girl." He then made no comment to police questions.

In the witness box Mr Porter, now 55, told the jury of 8 women and 4 men that he knew it was a hoax all along.

Under cross-examination by prosecutor Mr Noble, he was asked why he had referred to "claiming" the girl in Internet conversations with her. "You were planning to claim her virginity," he said.

The defendant denied the allegation, saying he simply drove to Luton to confront the people behind the hoax.

Mr Noble went on: "You were excited at the prospect of a young girl wanting to have sex with you."

He replied: "No. It was a game. I was playing a stupid game. I was amusing myself. It was a stupid game to play."

The defendant told the jury his GP had prescribed Viagra because he had been suffering from erectile dysfunction, but he said it did not work.

He is due to be sentenced on Friday January 27.