Manchester United are preparing to announce the signing of Fabio and Rafael Silva, Brazil’s answer to the Neville brothers. The 17-year-old twins, who are identical, are scheduled to arrive in Manchester on Monday to join United in a joint £5.2 million transfer from Fluminense, a deal that has been 2½ years in the planning.

Like Gary and Phil Neville, the Silva brothers are full backs, with Rafael operating on the right flank and Fabio on the left, even though both are right-footed. They caught Sir Alex Ferguson’s eye in a youth tournament in Hong Kong in 2005, during United’s preseason tour to Asia, and signed precontract agreements with the Barclays Premier League club when they turned 16 in July 2006. Initially the plan was for them to move to Manchester this summer, but the deal has been brought forward now that they have received the necessary paperwork.

The twins excelled for Brazil in the Under-17 World Cup finals in South Korea last August, with Fabio, the captain, finishing as his country’s leading scorer. Ferguson and Carlos Queiroz, the United assistant manager, are understood to be excited about the potential of the duo, even though they are unlikely to make more than the odd fleeting appearance in the first team in the immediate future.

“After eight visits to Manchester United, we will travel to come to live in England,” Fabio said. “In the last two years, we have visited many times. This time we are there for good.”

With the Brazilians being added to a pool of talent that includes Jonny Evans, who is on loan at Sunderland, Gerard Piqué and Danny Simpson, Ferguson believes that United are well stocked in defence for many years, but concerns remain over the prospect of losing Wes Brown, who has yet to agree an extension to his contract, which expires at the end of the season.