Manchester United are attempting to return to the summit of the Premier League with the most expensive squad ever assembled in the English game.

The arrival of Angel Di Maria this week takes the combined transfer fees of the United squad to an eye-watering £401.2million - and that figure could grow with new signings before the transfer window closes.

The value of United's squad now outstrips their neighbours and defending champions Manchester City, who are worth a collective £344.15m when the transfer fees are added up.

VIDEO Scroll down for Shaw and Herrera on target in United training

Expensive: Angel Di Maria's £60m move to Manchester United from Real Madrid has pushed the total transfer fees of United's squad beyond the £400m mark

Money men: The combined transfer fees of the United squad now exceed the £400m mark

Overtaken: United's summer buys have seen them leapfrog neighbours City as the Premier League's most expensively-assembled squad

BIG FIVE SQUAD TRANSFER FEES Manchester United £401.2m Manchester City £344.15m Chelsea £341.8m Liverpool £245.8m Arsenal £209.5m Advertisement

Chelsea come a close third on £341.8m following the acquisitions of Cesc Fabregas and Diego Costa over the summer.

City's title-winning squad from last season cost £364.7m to put together, while their successful team from the 2011-2012 season was worth £334.5m.

United have so far spent £131.7m on four players - Di Maria, Ander Herrera, Luke Shaw and Marcos Rojo - as Louis van Gaal desperately tries to strengthen a squad that slumped to seventh in the table last season.

But these big money signings are merely an escalation of United's exponential buying over the last decade with 17 members of the squad costing in excess of £10m when they arrived at the club.

Reinforcement: United announced the £16m signing of Marcos Rojo from Sporting Lisbon last week

Incoming: Luke Shaw was signed from Southampton earlier in the summer

Chris Smalling, for instance, cost £10m when signed from Fulham in 2010, Phil Jones cost £16.5m when he arrived from Blackburn in 2011, and Wilfried Zaha cost £15m. The much-maligned Anderson was £27m, Antonio Valencia £16m and Ashley Young £17m.

The result is by far the most expensively-assembled squad in the Premier League. And the numbers could increase further if United land £30m-rated Arturo Vidal from Juventus and other last-minute buys.

United have made Vidal their prime target following the arrival of Di Maria and are involved in negotiations with the Italian champions.

They are also interested in the Ajax defender Daley Blind, who is well known to Van Gaal, the former Holland coach.

Next up: United's spending could increase further if they secure a deal for Juventus player Arturo Vidal (right)

Dutch delight: Ajax and Holland defender Daley Blind (left) is also on United's radar

United's total transfer fees far outstrip those of title contenders Liverpool, who squad was put together for £245.8m, and Arsenal, worth a combined £209.5m.

As transfer fees grow ever-more extortionate, the price of assembling a title-winning squad will grow higher and higher.

Already, United have smashed the £400m mark. It surely won't be long before the half-a-billion point is reached.