THE 18th birthday party for the son of TV sports presenter Steve Rider turned into chaos when a CS gas canister was let off.

Emergency services rushed to the scene at The Pad bar at Wycombe Air Park in Clay Lane, High Wycombe, just before 11.30pm on Friday.

Around 150 panic-stricken youngsters evacuated the building, with many affected by breathing difficulties.

The party was a joint celebration for the Hurley-based ITV presenter's son and a friend.

Steve, who was there with his wife, said he was sure the attack was not carried out by any of the party-goers.

He said: "We were just looking after things front of house. Then wallop, something happened. There was an orderly mass-exodus with everyone coughing and spluttering."

During the same night, the Litten Tree pub in Frogmoor, High Wycombe, was hit by a similar gas attack.

An investigation has been launched by police after the attack at Wycombe Air Park Ambulance crews had to check around 150 people who were coughing and spluttering when CS gas was let off in the restaurant.

Two fire crews from High Wycombe attended to evacuate and ventilate the building.

The dad-of-two, who presents Formula One and Champions League coverage for ITV, said: "We are confident it was not one of the guests as they were all behaving themselves very well indeed."

His wife,Jane, added: "Everyone's instant reaction was to get out of there. I have never seen anything like it. It was all a bit of a blur.

"Suddenly you are enjoying yourself and the next you are hit with a feeling like if you had a really hot chilli pepper down your throat.

"Four or five girls were on the ground in the carpark unable to breathe because they had asthma.

"It just ruined what was a really lovely party.

"We stayed until about 1am to make sure everyone was okay.

"They both feel that they are certain it wasn't any of their friends. I think it's really pathetic and sad."

She also added two 18-year-old girls were taken to hospital and released later that night.

"My worry is that it's the start of stupidness with people to spoil other people's enjoyment which I think is terrible," she added.

Helen Robinson-Gordon, communications manager for South Central Ambulance Service, said: "Four crews and a single responder attended.

"We did convey a female with respiratory difficulties to hospital and checked about 100 people on the scene after reports that they had been affected by a substance that caused breathing difficulties."

Police confirmed the incident was not terrorism-related and are now investigating the possibility of criminal damage.

Police would like to hear from anyone who witnessed the incident. If you have any information contact Thames Valley Police on 08458 505 505 or Crimestoppers anonymously on 0800 555 111.