COLIN McRae's father yesterday paid tribute to the rally driver who was killed in a helicopter crash which also claimed the lives of his five-year-old son and two others, including a six-year-old boy.

McRae, 39, died in the crash with his son Johnny, his long-time friend Graeme Duncan, 37, and Johnny's friend, Ben Porcelli.

Jim McRae, also a former champion rally driver, said the former world champion was a "great son, a loving husband...and a fantastic father". He added that Johnny was a "great wee guy" who he had hoped would one day emulate his famous father.

Investigations are under way into the helicopter crash which happened in the grounds of McRae's Jerviswood House mansion, near Lanark, as it was landing on Saturday afternoon. Eyewitnesses said the aircraft turned on its side and crashed into trees close to the house.

Jim McRae said: "It is unbelievable that Colin and Johnny's lives have been taken so prematurely and in such a tragic manner.

"Colin was a great son, a loving husband to Alison and a fantastic father to Johnny and his big sister Hollie. Johnny was a great wee guy, spending every spare minute with his dad, and even at this early stage it looked like he had (racing) potential.

"Our thoughts are also very much with the families of Ben Porcelli and Graeme Duncan. Ben was a great buddy of Johnny's and they had always spent a lot of time together both in and out of school. Graeme had been a close friend of Colin's since their schooldays and was back in Lanark on holiday."

Ben's parents, Mark and Karen, who live in Lanark, said in a statement: "We are absolutely devastated. Ben was a charming, fun-loving and caring wee boy, the best boy in the world who enjoyed great times with his wee pal Johnny. It is just so tragic that their lives have been cut so short."

The Twin Squirrel helicopter burst into flames around 4.10pm on Saturday after a short flight from nearby Quarter, and around 40 firefighters battled the blaze. Police sealed off the secluded estate and a tent was erected for forensic investigation.

A post-mortem examination will be carried out on the bodies within the next few days, and police are preparing a report for the procurator fiscal.

Chief Superintendent Tim Love, divisional commander of Strathclyde Police's South Lanarkshire Division, said: "It appears that the helicopter got into difficulty and crashed within the grounds of McRae's family home. Our officers are working closely with the Air Accident Investigation Team at the scene."

McRae's co-driver of 10 years, Nicky Grist, said: "Colin was always regarded as being a bit of a risk-taker in cars, but when it came to flying a helicopter he was a totally different man.

"The one thing he always told me, he said: You don't mess about with a helicopter. They are bigger and better than I am and you have to drive them as such'."

Aviation expert David Learmount said a mechanical error was possible.

He said: "He would have made a judgment about the weather, and I don't think he would have misjudged that.

"It's pure speculation but my suspicion would be something went wrong with the helicopter."

In a separate incident yesterday, a close friend of McRae escaped unhurt after crash-landing a helicopter. Subaru rally team chief David Richards, 55, and his wife Karen, 53, were returning from the Belgian Grand Prix when they experienced mechanical problems and their aircraft came down at 2.15pm near to North Weald Airfield, Essex.

Mr Richards is chairman of Prodrive, which runs the Subaru World Rally Team, and met McRae when he raced for them.

A Prodrive spokesman said: "David and Colin were great friends and it's an amazing coincidence that this has happened. David is devastated about what has happened to Colin.

"We are just thankful he and Karen are okay."