Jose Mourinho showed he meant business at Manchester United last summer when he splashed approximately £150 million on new signings.

Zlatan Ibrahimovic joined on a free, while Paul Pogba (£89m), Henrikh Mkhitaryan (£26m) and Eric Bailly (£30m) all arrived in big-money moves.

By signing so much quality in one window, Mourinho sent a message to United's rivals that they're ready to once again fight for the Premier League title.

It hasn't quite worked out that way, though.

United may be on a 24-game unbeaten run in the league, but they're currently fifth in the table and with an outside chance of making the top four.

Indeed, winning the Europa League is looking like their best passage into the Champions League for next campaign.

Mourinho's first season in charge hasn't quite lived up to expectations and it's believed he will look to overhaul his squad once again this summer.

The Portuguese's biggest task is replacing Ibrahimovic, whose contract will expire at the end of the season after suffering a long-term knee injury.

Among those rumoured to replace the 35-year-old striker are Antoine Griezmann and Romelu Lukaku, who would both cost upwards of £70 million.

Elsewhere, a new goalkeeper could be in the offing should David de Gea leave, while defensive and midfield reinforcements are also needed.

Another summer of mass spending is expected but according to Sky Sports' Guillem Balague, United are prepared to splash an obscene amount.

Prepare yourselves. According to the Spanish football expert, Mourinho is allowed to spend anywhere between £300-£400 million to get who he wants - if not more.

"I am reliably informed that Manchester United are willing to spend in the region of £300m to £400m this summer to achieve what they want," Balague said. "They could spend more if necessary."

Just let that sink in for a minute. Also bear in mind that the record amount spent by a club in one transfer window is £195 million by Real Madrid in 2009. Staggering.

Balague also touched upon the future of De Gea and claimed that while Los Blancos are interested, the Spaniard wants to stay at United.

"Do Real Madrid want De Gea? You bet they do," he added. "What surprises me, however, is why a club like Manchester United - that have no need to sell him - would be prepared to let him leave.

"I'm sensing a hidden agenda. There are plenty of rumours that De Gea is Real Madrid-bound, but I am not convinced that this is the wish of the current United goalkeeper."