THERE was a massive breakthrough in the investigation into the July 7 London bombings last night when police made their first significant arrests in connection with the suicide attacks.

Three men were arrested by Scotland Yard counter terror detectives in the North - two of them as they were about to leave the country.

The two - aged 23 and 30 - were arrested shortly before 1pm at Manchester airport as they prepared to board a flight to Pakistan.

They had gone through passport control but were still in the terminal building at the time of the arrests.

The third man, aged 26, was held at his home in Leeds shortly after 4pm.

Officers also carried out a series of raids on houses in the Beeston area of Leeds, where three of the July 7 bombers had strong connections.

Last night, Beeston once again appeared to be the focus of the police investigation into the July 7 attacks, in which 52 people were killed.

Police have been investigating how the four suicide bombers, who exploded rucksack devices on three Tube trains and a bus, were supported and financed.

Senior officers have always said that members of their support network were still at large.

One of the houses raided yesterday was in Colwyn Road, the same road where the Aldgate bomber, Shehzad Tanweer, lived.

The other four houses were in Cardinal Road, Firth Mount, Tempest Road, and Rowland Place, West Yorkshire Police said.

Searches were continuing last night, but police sources said they were not expecting to find bombs or bomb-making equipment.

All three arrested men are understood to be from Leeds. By 7pm last night, two had arrived at London's high-security Paddington Green police station. The third was expected to arrive later.

Interviews are likely to start today. Under new anti-terror laws, police can hold them for a maximum of 28 days.

The men were arrested on suspicion of the commission, preparation, or instigation of acts of terrorism under the Terrorism Act 2000.

A Scotland Yard spokeswoman said last night: "Since July 7, 2005, when 52 people were murdered, detectives have continued to pursue many lines of inquiry both here in the UK and overseas.

"This remains a painstaking investigation with a substantial amount of information being analysed and investigated.

"As we have said previously, we are determined to follow the evidence wherever it takes us to identify any other person who may have been involved, in any way, in the terrorist attacks.

"We need to know who else, apart from the bombers, knew what they were planning. Did anyone encourage them? Did anyone help them with money, or accommodation?

"The Metropolitan Police remain committed to discovering all we can about the events leading up to the July 7 attacks."

Speaking outside the house in Firth Mount, Chief Superintendent Mark Milsom said: "It's important to stress a few things.

"First of all, the people have been arrested in connection with the events that happened back in London two years ago. This is not a new inquiry.

"The other thing to stress is that what we're looking for at these addresses at this moment is not something that is going to threaten or put anybody at risk."

Chief Supt Milsom said his role was to keep the public as fully informed as possible.

He went on: "There will be more officers patrolling in the area and visiting people to reassure them, but they are very much local neighbourhood policing officers."

A neighbour who lives a few doors from the house said she knew the family who lived there and said the taxi driver was "a very lovely man".

She went on: "I've seen him in the street a lot.

"He's a very nice bloke, plays cricket with the kids, and has even given taxi rides to people living round here if they need to go places for free.

"I don't know the woman. She is much more private and doesn't talk to anyone.