A full military rehearsal for the funeral of Baroness Thatcher, who was born and brought up in Grantham, has taken place in the early hours in London.

Major Andrew Chatburn, the man in charge of choreographing the parade, said the rehearsal "went very well" and claimed it was "vitally important" to stage a trial of Wednesday's event.

More than 700 serving Armed Forces personnel gathered in central London before dawn as a Union flag-draped coffin was carried on a horse-drawn gun carriage from St Clement Danes, the church of the Royal Air Force, down the Strand to St Paul's Cathedral.

Maj Chatburn, ceremonial staff officer for the Household Division, who was also behind the royal wedding procession two years ago and last year's Diamond Jubilee parade, said: "Timings are most important. We will learn something quite significant this morning about the timings, and to familiarise the troops of their duties.

"Bearing in mind these are sailors, soldiers and airmen who have come in to do this specific task from their routine duties, so it's new to them.

"They need to see the ground as well so they can get a feel for how it's going to go and they can perform their duties with confidence on the day.

"I thought it went very well."

The procession band played the funeral marches of Chopin, Beethoven and Mendelssohn as it made its way along the deserted streets.

During the rehearsal the military and police wore their working dress and high visibility clothes respectively, but they will be in ceremonial uniform on Wednesday.

The pensioners from Royal Hospital Chelsea did not take part due to the early start, but they will line the west steps of St Paul's for the real event.

Maj Chatburn said: "The point of the rehearsal is to prove the route, make sure that the soldiers, sailors and airmen are familiar with their duties and to prove the timings.

"There is always scope for error but we try to eliminate that as much as we possibly can.

"We'll go back now, we'll have a debriefing and we'll take the points from that.

"We'll address whatever we have to address. If it's additional rehearsals in barracks we'll conduct those rehearsals and we'll get it right on the day."

Maj Chatburn said the thousands of people lining the streets on Wednesday will create issues that could not be replicated in the rehearsal.

"That creates an atmosphere and for the horses in particular that is another challenge for them.

"But they will handle that because the horses themselves are used to doing duties in central London with lots of crowds around."

He added: "Having a large public presence always concentrates the mind that little bit more for everyone."

Deputy Speaker Nigel Evans MP, speaking on ITV Daybreak, defended the cost of the funeral.

He said the Bishop of Grantham, the Rt Rev Dr Tim Ellis, had "got it wrong" over his description of the scale and the cost of the funeral as a "mistake" which may play into the hands of extremists.

"He has got it wrong," he said.

"I do not know where the £10 million figure has come from. It is going to be substantial sums but when you have got the Queen and other world leaders coming in for this funeral, then you are always going to have substantial security costs.

"So we are where we are."

He added: "We have just had an amazing Olympics which cost billions, we have had an amazing Diamond Jubilee which cost well in excess of £10 million - the world was looking at London, we do pomp and ceremony incredibly well. We are talking about marking the passing of the first woman prime minister in this country and indeed of the western world.

"Yes, I think it is going to be done in the right way but pomp and ceremony is something we do awfully well."