A LANE of the M40 motorway was closed off by police yesterday amid reports that liquid explosives were found by teenagers at the roadside.

Two 13-year-olds cycling through Fennell's Wood, Loudwater, on Wednesday night discovered two bin liners, which they say contained bottles of liquid.

The youngsters tipped out the bags' contents which then smoked and bubbled on the ground.

The terrified teenagers fled from the wood and dialled 999.

They were being interviewed by anti-terror police at a secret location in South Bucks yesterday.

Police told one of the boys' mothers that what they discovered was an "important find".

The mother, from Hatters Lane, High Wycombe, added: "We didn't know what it was, but the police have said that it is bomb-making equipment."

One of the boys, Shane Bartlett, said told The Times: "Arron kicked one of the bags and felt something inside so we opened it and there were bottles inside.

"We opened one and poured some on the ground and it started bubbling all over the place. We thought it was dangerous, so we ran away."

The discovery was close to Loudwater Combined School.

Officers from the Metropolitan Police descended on the stretch of motorway between junctions three and four.

The slow lane of the eastbound carriageway between junctions three and four was cordoned off and reduced to two lanes as a precautionary measure, causing tailbacks.

Forensic teams continued the investigation on Friday morning.

Thames Valley Police officers are standing guard at the scene of the roped-off area of Fennell's Wood.

The Met would not confirm or deny that liquid explosives had been found.

A spokeswoman said: "We are not prepared to discuss what the items are and we are not prepared to speculate whether the items are linked to any ongoing investigations."

The site of the discovery is close to Booker Common, which was searched following the alleged airliner bomb plot. King's Wood, on the other side of High Wycombe, was also searched.

Police confirmed last month that they had discovered bomb-making equipment in relation to the August 10 foiled plot to blow up transatlantic jets.