I will keep family safe - Beckham

"The first role of a father and husband is to keep his family safe," the England and Manchester United footballer said in a statement on Sunday.

Police are holding nine people in custody over the alleged conspiracy to snatch pop star Mrs Beckham and seek a £5m ransom.

Officers raided premises in the capital's Docklands area and Morden, south London.

The couple and their two sons, three-year-old Brooklyn and baby Romeo, have been keeping a low profile at their home in Alderley Edge, Cheshire.

Four men and one woman were arrested in two separate raids in London on Saturday morning by officers from Scotland Yard's Serious and Organised Crime Command unit, known as SO7.

Another four people, including a second woman, were arrested in further operations conducted late on Saturday and early on Sunday, police said.

Scotland Yard swooped on the nine after receiving information from the News of the World about an alleged plan.

Beckham thanked the police for their "professionalism and support", saying they were "unbelievably effective".

Undercover sting

"Because of this incident we will be reviewing our security arrangements again with help from both the police and the security experts at Manchester United," he said.

Mrs Beckham had earlier said she was in "absolute and total shock" at the revelations.

Contractors have been checking security at the Beckham's second home, at Sawbridgeworth in Hertfordshire.

David Beckham's football club, Manchester United, said it was confident its security arrangements were appropriate.

A club statement issued on Sunday, read: "We are very concerned by these developments because the safety and welfare of our players and their families is of paramount importance to Manchester United.

"However, we are confident that the security arrangements around the club's players and staff are entirely adequate, although those arrangements are always under constant review."

'Children targeted'

The NoW said undercover reporters had infiltrated a gang of art thieves and discovered they were also planning to kidnap the former Spice Girl and possibly her two sons.

She told the newspaper the alleged plot had "scared the life out of me".

News of the World managing editor Stuart Kuttner told BBC News 24 his reporters had become so close to the gang, they had even been recruited into positions central to the alleged plot.

"The plan was to kidnap Victoria Beckham, to take with her either or both the children if perchance they were with her... to secrete them in a safe house and to demand a ransom of £5m," he said.

Previous threat

The nine people arrested in connection with the alleged kidnap plot are being held at unnamed police stations across London, where they are being questioned about conspiracy to kidnap and theft.

At least five of those being held are understood to be Romanian or Albanian.

The NoW said the gang planned to sedate Victoria with a chemical spray and hold her in a house in Brixton, south London.

Deputy editor Andy Coulson said the plans were fairly well formed.

"They knew where they were going to carry out the kidnap, they knew how, they knew when," he said.

Police said they were grateful to the newspaper, which had assisted in the "recovery of a number of valuable items and in preventing any other offences."