Swansea City completed the double signing of Tom Carroll and Martin Olsson on Tuesday, taking their January business past £12m.

Carroll, 24, played on loan at the Liberty Stadium two seasons ago and has rejoined permanently from Tottenham for an initial £4m.

The central midfielder has agreed a three-and-a-half year deal and Sportsmail understands Tottenham will net 50 per cent of any profit if Swansea go on to sell Carroll for more than £4m.

Martin Olsson has completed his £4million move from Norwich

Carroll came through Tottenham’s academy after joining in 2008 but has struggled for playing time with only three Spurs starts this season.

His arrival in south Wales came just hours after Swansea signed Martin Olsson for £4m from Norwich. The left-back, 28, has been monitored by the club since first being identified as a target during Garry Monk’s reign and has joined on a two-and-a-half year contract.

A left-back was on Swansea’s agenda for this transfer window, but the move was given greater urgency after Neil Taylor suffered a fractured cheekbone in training last week.

The signings of Carroll and Olsson followed the arrival of Holland international winger Luciano Narsingh for £4m from PSV Eindhoven last week, with Paul Clement looking to do major work to the division’s bottom-placed side this month.

Tom Carroll completed his move to Swansea from Tottenham on Tuesday afternoon

Carroll said: 'It’s been a couple of years since I’ve been here – there have been some changes – but I’m excited to be back.

'It definitely helps knowing quite a few of the lads from my loan spell, while I know (assistant coach) Nigel Gibbs and (head of physical performance) Karl Halabi too. 'Knowing the players and staff allows you to settle quicker than normal.

'It can take time to settle in at a new club, but having some familiar faces around the place will help me get going straight away. 'I know what the club is about too, and I know the playing style suits me so that was a big factor in me coming here.'

The prime target for Clement remains a centre-half, with Swansea having failed miserably to cope with the summer departure of Ashley Williams to Everton. The club have so far conceded a league-high 49 goals, including shipping at least three goals in seven of their past nine fixtures.

Steven Caulker was initially on their shortlist but interest has since faded.