ALAN Pardew will prioritise the purchase of a central defender in next month's transfer window, and has already begun the process of sifting through a list of potential signings.

While the window does not officially open until Sunday, the Newcastle manager is understood to have inquired about the potential availability of Ajax's Jan Vertonghen and West Ham United's James Tomkins as he looks to bolster his defensive options for the second half of the campaign.

At the start of the month, Pardew expected to be chasing a striker in January, but with Steven Taylor set to be out for the remainder of the season after rupturing his Achilles tendon, priorities have shifted.

The collapse of Modibo Maiga's proposed move to Tyneside following a failed medical has freed up resources, and senior St James' Park sources have confirmed that if only one player arrives next month, it will be a centre-half.

Newcastle's scouting team have watched a number of defenders in the last three weeks, with Pardew keen to move as quickly as possible despite Mike Williamson's welcome return to action in Monday's 2-0 win at Bolton.

Pardew's number one target is believed to be Vertonghen, a 24-year-old Belgium international who has spent the last five seasons on Ajax's books.

He will not be cheap, as Ajax have previously valued him at around the £10m mark, but his age and experience fit the template that Newcastle owner Mike Ashley has previously stuck to, and the club's chief scout, Graham Carr, is known to be a fan.

Newcastle officials have made preliminary inquires with both their counterparts at Ajax and Vertonghen's representatives, and are aware of competing interest from both Tottenham and Arsenal.

Consequently, Pardew continues to consider alternative candidates, and Tomkins is regarded as a leading option despite former Newcastle boss Sam Allardyce's reluctance to sell the 22-year-old.

Tomkins has been a key component in West Ham's defence as the London club have established themselves in the Championship promotion places in the first half of the season.

Pardew, a former West Ham boss, has sounded out the possibility of securing the defender's services, and has even raised the possibility of a £2.5m bid.

Allardyce's response was to publicly insist that Tomkins will not be leaving Upton Park next month, but a decision could be taken out of his hands if Newcastle were to table a bid that West Ham's owners felt they could not turn down.

The need for a defensive reinforcement has been glaringly apparent in recent weeks, with James Perch and Davide Santon, both full-backs by trade, struggling to plug the gap left by Taylor's injury.

Things were better at Bolton two days ago thanks to the return of Williamson following a four-month lay-off because of knee and ankle injuries.

The former Watford centre-half slotted in seamlessly as Newcastle recorded their first clean sheet on their travels since September 12, and was understandably delighted to be back in the fray following an injury that proved much more serious than initially thought.

“At the time, I didn't think the injury would be as serious as it proved,” said Williamson. “Initially, I tried to run it off because I didn't know what I had done. But it turned out to be a strange twist involving my knee and my ankle.

“When it was looked at the next day, I quickly realised the length of time I was going to be out for. It's been a long time to reflect, but I've done a lot of good rehab and the medical team here have worked me hard.”

With Taylor expected to miss the majority of the rest of the season, Williamson finds himself with an ideal opportunity to reclaim the first-team spot he ceded towards the end of last term.

The 28-year-old played 16 matches during Newcastle's successful Championship campaign, and started 28 of the 38 top-flight matches last season. Nevertheless, unlike Taylor and Fabricio Coloccini, it feels as though he is still to truly establish himself as a first-choice pick.

“I played the last half of the Championship season and the whole of the first season in the Premier League barring the last few games, so I don't really feel as though I have to establish myself or anything like that,” countered Williamson.

“I've had a good period in the team here, it's just unfortunate that I've also had a couple of injuries along the way. It would be nice to stay injury free now and just concentrate on putting some good performances in.”

Monday's display was certainly impressive, with Williamson combining with Coloccini to mark Ivan Klasnic and David Ngog out of the game. Bolton boss Owen Coyle introduced Kevin Davies and Tuncay Sanli in an attempt to change things late on, but the pair were equally well shackled as Newcastle claimed a much-needed victory.

“It's easy to come into a team where everyone works as hard as they do here,” said Williamson. “We've got a good team spirit and there's a lot of confidence here at the moment.

“From the first game of the season, the lads have kept the same momentum, both in games and in training. The spirit is high and everyone is positive.”