The Sunderland striker moved back to Ninian Park in January as part of a loan deal which both clubs agreed would become a permanent move over the summer.

And July 1 is the day when the Welsh club officially became Chopra's employers.

The Gazette understands that the undisclosed fee is actually £3m – £2m less than Roy Keane paid for him two years ago – with Cardiff making an initial downpayment of £500,000 with the rest to be paid in instalments.

Although Chopra only officially became a Cardiff player today, he has already linked up with the Bluebirds for pre-season training.

The Tynesider's signing smashes Cardiff's previous transfer record, the £1.7m paid for Stoke City's Peter Thorne in September 2001.

The move represents an excellent bit of business by Cardiff, but possibly a decent move as far for Sunderland too.

Chopra was Cardiff's star player before Keane signed him – scoring 22 goals in 42 league starts after his move from Newcastle United in 2006.

But the £5m the Wearsiders paid for him was always regarded as something of an over-inflated price.

Chopra scored a respectable eight goals for Sunderland in 22 starts but, as at Newcastle, rarely looked like a top Premier League striker.

He scored some vital goals nevertheless, none more so than the one at Villa Park in April 2008 which earned Sunderland a 1-0 win and their first away win of the season.

That goal and that result was credited by many within the club as the moment when the battle to avoid relegation turned in their favour.

But Chopra failed to maintain his progress, and after a shocking miss against Newcastle in the Tyne-Wear derby at St James's Park, which raised the subject of his Geordie allegiances, he never played for Sunderland again.

Cardiff chairman Peter Ridsdale instantly spotted the predicament Chopra was in, and was on the phone to Niall Quinn within hours offering the striker an escape route.

Although his impact at City second time around was more modest - four goals in 16 appearances - he is now perfectly poised to rebuild his career and put the Bluebirds among the front-runners for promotion from the Championship next season.