Stefano Baldini won the men's marathon as Briton finished an agonising fourth for the second Olympics.

But a security breach overshadowed the result as Brazilian Vanderlei de Lima was attacked by a spectator as the athletes approached the 23-mile mark.

The man, wearing an unusual multicoloured costume, ran from the pavement to De Lima's left and grabbed the Brazilian, pushing him into the crowd on the right.

Dressed in a kilt and wearing a beret with some writing scrawled on his back, the gate-crasher bore a resemblance to the Irishman who interrupted the British Grand Prix at Silverstone last year.

Former Catholic priest Cornelius Horan ran on to the main Hangar Straight in that race as the F1 cars sped around the circuit and was subsequently handed a two-month prison sentence.

The drama arose with three and a half miles of the race remaining, and De Lima, who was leading the race but was being sucked in by a group of athletes, was held up by approximately 10 seconds.

He emerged from the shocked crowd holding his right thigh and it was not clear whether De Lima had been injured in the incident.

He almost stumbled over the line at the end, taking third place and the bronze medal, but for De Lima it was a case of what might have been without the earlier drama involving the intruder.

The worry for the Athens Olympic Committee (ATHOC) will be that although there are road-side barriers along the course, the spectator was not stopped by security and briefly chaos ensued.

Clearly it could have been a far more serious situation had the meddler carried a weapon.

The International Olympic Committee's executive board went into immediate discussion over the incident ahead of tonight's showpiece closing ceremony.

The face of the race was already changing before the intrusion, with De Lima's lead being gobbled up quickly.

Soon after the incident, he was passed and had to settle for the bronze.

Taking the gold medal was Italian Stefano Baldini, while the silver medallist was American Mebrahtom Keflezighi.

De Lima finished in front of Briton Jon Brown, who finished fourth, just as he had done in Sydney four years ago.

For a long while, it looked as though Brown might get among the medals.

The 33-year-old commendably kept pace with the pack of athletes who were chasing down De Lima.

Brown worked his way through the field from 67th place after five kilometres, to 50th after 15km, to seventh after 25km, and then remarkably to second place after 30km.

He had finished fourth in the Sydney marathon and was looking in good shape to secure a similarly lofty position again.

The turn of pace from De Lima had surprised his rivals, and he led by almost 50 seconds at one stage.

There was no immediate response, which was surprising given the standard of athletes in the race.

World record holder Paul Tergat of Kenya was in the pack which contained Brown, as were Ethiopian Ambesse Tolosa, Morocca Jaouad Gharib, American Mebrahtom Keflezighi and Italian Stefano Baldini.

Kenyan Eric Wainaina was also up there.

De Lima had apparently gone out too quickly, and too soon, and regardless of the attack, it was hard to see him maintaining his lead.

Baldini completed the course aggressively, clocking 2:10:55, while Keflezighi came home in 2:11:29, ahead of Lima who struggled on his lap of the Panathinaiko Stadium, finishing in 2:12:11.

Brown, missing out on a medal again, was officially timed at 2:12:26.

Responding to the intruder attack on De Lima, the IOC released a statement which read: "The IOC is saddened by the incident.

"The executive board has met. However, we must await the decision of the IAAF jury which is meeting now.

"At that time, once they have taken their decision, we will give our position.

"All this will be in time for the medal ceremony."

De Lima was the focus of attention once he crossed the finish line, and he was quick to state that the incident had ruined his plans.

"I trained a lot for this and I'm very happy to win this bronze medal.

"If that spectator didn't jump in front of me in the middle of the race, who knows what would have happened.

"Maybe I would have won. It disturbed me a lot," he said.

"For me it was very difficult because I didn't know what he had with him. I was very afraid.

"I lost my rhythm and I had to get back to the rhythm on the street and it was very difficult. I could have done better."