Organisers claim 200,000 joined the demonstration, although police put the numbers closer to 100,000.
The protest was overshadowed by the bombs in Turkey, but was described as good-natured and non-violent.
Meanwhile Mr Bush carried on with his engagements, which culminated in a banquet for the Queen at the US Ambassador's residence in Regents Park.
About 60 VIPs at the banquet included actor Sir Michael Caine, newscaster Sir Trevor McDonald and the Prince of Wales and the Duke of York.
Send us your pictures of the demonstrations
The demonstration - the biggest in London on a weekday - culminated in Trafalgar Square with music and a carnival atmosphere.
Its climax was the toppling of an effigy of Mr Bush, echoing scenes from the fall of Baghdad.
A few minor scuffles broke out in the square and a breakaway group tried to get into the banquet, but there was no significant trouble.
One protester delivered a parting shot at the president by throwing an egg at the presidential cavalcade at about 2320, police said.
Protesters toppled a statue of George Bush
The egg missed, but the man was arrested on suspicion of public order offences.
Security in the capital was extremely tight ahead of the march, with 5,123 police officers deployed on the streets.
In all, there had been 67 arrests by Thursday night as part of the special security operation. The egg-thrower was the 67th.
Two police officers were injured during the protest, police
A 21-year-old constable suffered a facial injury which needed stitches, and another police constable, aged 29, was also treated for a leg injury in
commissioner of the Metropolitan Police Andy Trotter said: "We've
had a very good-tempered march and there have been no particular problems."
Mr Bush and Mr Blair made a joint appearance to condemn the Turkey bomb attacks and reiterate their determination to fight terror.
"Once again, we must affirm that in the face of this terrorism there must be no holding back, no compromise, no hesitation in confronting this menace, in attacking it wherever and whenever we can and in defeating it utterly," said Mr Blair.
"They are not going to succeed. The terrorists hope to intimidate. They hope
to demoralise. They particularly want to intimidate free nations," said Mr Bush.
The Met's Andy Trotter said the attacks in Istanbul underlined that his officers were working for the protection of demonstrators as much as for Mr Bush.
Westminster Abbey to lay a wreath and meet families of soldiers killed in Iraq
Talks with Tony Blair at Downing Street
HIV/Aids discussion at Downing Street
Stop The War Coalition March leaves Malet Street, marching down Whitehall to Trafalgar Square
Bush hosts banquet for Queen at US Ambassador's residence
"As we have seen, terrorists really don't care who they blow up or who they
target," he said.
"They would have no compunction to take out demonstrators, no compunction in
any way at all. And that's a very difficult message to get across to some
There was major disruption to the city centre earlier in the day as the march wound its way towards Trafalgar Square from Euston, via Parliament Square and Whitehall with roads around the route being closed as the marchers approached.
Scotland Yard had been concerned that as many as 1,000 European anarchists would target the event for their own purpose but the threat failed to materialise.
In Scotland, the Scottish Parliament was suspended after a protester dressed in a
George Bush mask shouted anti-war slogans from the public gallery during a
debate on Iraq.