Tottenham Hotspur have agreed everything with Toby Alderweireld and Atlético Madrid over the Belgium defender’s transfer to White Hart Lane, from the £11.4m (€16m) fee to the personal terms on a long-term contract. Alderweireld is even understood to have taken his medical.

The deal, though, rests on Atlético being able to resolve a dispute with Southampton, where Alderweireld played last season on loan. The south coast club had the option to make the 26-year-old’s transfer permanent for €8m, unless Atlético paid them €2m to cancel the arrangement.

Southampton took up the option and they say that Atlético failed to meet the deadline on the cancellation fee, meaning that the player ought to be theirs. The reality, though, is that because Southampton lack the will of Alderweireld, it is impractical for them to force him to come to them. Les Reed, Southampton’s executive director, is instead in negotiations with Atlético over a settlement that relates to the €2m non-payment.

Tottenham say that Atlético promised they have the authority to sell Alderweireld to whomever they choose and they have treated the pledge in good faith, moving quickly to close their side of the deal. They consider the argument between Atlético and Southampton to be nothing to do with them.

Mauricio Pochettino, the Tottenham manager, has overhauled his options at the back and Alderweireld stands to become his third signing of the summer, following the centre-half Kevin Wimmer for €6m from Cologne and the right-back Kieran Trippier for £3.5m from Burnley.

Alderweireld is attracted by the prospect of partnering his international teammate Jan Vertonghen in central defence – the pair currently occupy the full-back positions for Belgium, with Alderweireld on the right and Vertonghen on the left.

Alderweireld is grateful to Southampton, where he thrived after a difficult season at Atlético, but he considers Tottenham to be the surer bet for regular European football. He would also be able to fly home more easily from London – there are direct flights to Deurne, the small airport that serves his hometown of Antwerp.

Southampton have completed the signing of the versatile defender, Cuco Martina, from the Dutch side Twente on a two-year contract.

He arrives because the first-choice left-back, Ryan Bertrand, is out for a number of weeks after knee surgery. Martina’s natural position, though, is right-back.