Power rankings: the 10 best League One transfers ahead of January deadline day - featuring Portsmouth, Hull, Ipswich and Charlton

Pompey and their rivals have until 11pm on Monday night to complete their business.

So far, the Blues have signed four players in Harvey White (Spurs), Charlie Daniels (Shrewsbury), George Byers (Swansea) and Lewis Ward (Exeter).

But how do Pompey’s transfers compare to the rest?

The likes of Hull, Doncaster, Lincoln and Sunderland – all also pushing for promotion – have strengthened their respective squads.

Ahead of deadline day, we’ve ranked the top 10 transfers that have taken place throughout January...

10. Ellis Simms (Everton-Blackpool) – loan

Seasiders boss Neil Critchley might be a former Liverpool under-23s coach – but it was the blue half of Merseyside he raided.

Simms has been granted his first loan away from Goodison Park after netting eight times in 12 matches for Everton under-23s this season.

The Oldham-born ace made a dream start at Bloomfield Road, firing a double in a 5-0 win over Wigan on debut.

Simms, 20, doesn’t count toward salary cap rules and looks a decent bit of business.

9. Luke Thomas (Barnsley-Ipswich) – loan

Paul Lambert’s under significant pressure after the Tractor Boys dropped more points against Crewe on Saturday.

However, he’ll be hoping Thomas can give his side an upturn in form.

The winger was impressive at Coventry two seasons ago in the third tier, earning him a big-money move to Barnsley.

Thomas fell out of favour at the Tykes this season, having made 41 appearances last season, and will be a potent asset to Ipswich if he fires on all cylinders.

8. Jayden Stockley (Preston-Charlton) – loan

Lee Bowyer has certainly bolstered his forward options this month.

He spoke of his delight to win the race for Stockley’s signature, with the likes of Sunderland and Hull also reportedly keen.

The ex-Pompey striker has spent the past two years in the Championship.

While Stockley wasn’t a prolific scorer at Deepdale, he’s a handful for defences and made a good debut in the Addicks’ 1-0 win at MK Dons on Tuesday.

7. Kevin Stewart (free agent -Blackpool)

It was a surprise how long the midfielder was without a club for after departing Hull at the end of last campaign.

From the outside looking in, it seems there was a reluctance to drop down to League One, as well as perhaps being short of Championship suitors.

In the end, however, the ex-Liverpool and Spurs man has had to settle for a move to the third tier in the end.

On paper, Stewart is a Championship player. He was a regular for Hull when fit and had been training with Premier League hopefuls Brentford earlier this season.

If he gets up to speed swiftly, the 27-year-old could be a classy operator for Blackpool.

6. Dan Crowley (Birmingham-Hull) – loan

Personally watched by Arsene Wenger before joining Arsenal at just 15, the attacking midfielder has always had a decent reputation.

Crowley’s never quite hit the heights many predicted but he’s a mercurial talent nonetheless.

The former England youth international, 23, could finally light the touchpaper to his career, though, as Hull aim for an immediate Championship return.

Crowley helped Grant McCann’s side to a 1-0 win over Swindon on Saturday, catching the eye with his performance.

5. Charlie Daniels (Shrewsbury-Pompey) – free transfer

The Blues’ interest in the veteran left-back emerged after Cam Pring’s loan spell was cut short by Bristol City.

Yet there is an argument Daniels is an upgrade on Pring given he was playing in the Premier League last season.

Granted, the ex-Bournemouth favourite has had his injuries but proved he’s over them by featuring 16 times for Shrewsbury in the first half of the season.

Daniels adds an immense amount of experience to Kenny Jackett’s side in their bid for promotion, along with quality crossing and set-piece delivery.

4. Gavin Whyte (Cardiff-Hull) – loan

The Northern Irishman drops back down to League One after earning a move to south Wales from Oxford for a seven-figure fee in July 2019.

That was after Whyte spent just 12 months at the Kassam Stadium, scoring nine goals in 47 matches.

With a Tigers front line that already brags the likes of Malik Wilks and Keane Lewis-Potter, Whyte provides the Tigers with even more strength.

3. George Byers (Swansea-Pompey) – loan

Kenny Jackett was chasing a centre-midfielder from the day the window opened.

The Blues boss coveted box-to-box player capable of adding quality to his engine room.

Pompey had to wait for their man – and they’ll be hoping patience reaps rewards.

Byers was a regular for a Swans side that went agonisingly close to reaching the Premier League last season, scoring five goals in 39 games.

He’s had his injuries but, if over them, will add real Championship quality to Pompey.

2. John Bostock (free agent-Doncaster) – free transfer

Captain Ben White’s departure to Preston was an almighty blow for the Yorkshire outfit.

Yet the arrival of Bostock as his replacement proved just the tonic for Donny fans’ disappointment.

It’s been regarded as a coup that the 29-year-old was prised to the Keepmoat, dropping down to League One having played in the top flight in France, Turkey and Belgium.

Bostock is yet to feature for Rovers but there’s a general feeling he will provide a touch of class.

1. Josh Sims (Southampton-Doncaster)

It won’t exactly please members of the Fratton faithful that a Southampton loanee is playing a key role in a rival’s promotion push.

Sims has been Darren Moore’s chief attacking threat this season and Donny fans were gutted when he returned to St Mary’s earlier this month.

It was expected that the 24-year-old would join a Championship club but an injury meant second-tier suitors backed off.

Sims has certainly given an already burgeoning Doncaster side a huge fillip.