Roy Keane has accused Manchester United of cutting corners in the transfer market.

The Reds have taken the first steps in strengthening their side by signing the Spanish midfielder Juan Mata for £37m from Chelsea, but it has become clear that their new manager David Moyes will need to spend big in the summer transfer window if he is to halt a decline that has seen the champions slide to seventh in the Premier league.

Since the Glazers took over the club in May 2005, they have spent over £696m on interest fees, bank charges and debt repayment, and around half that much on players: £382m.

Keane told itv.com: "They've kind of cut corners in terms of transfers in the last few years, they've not gone out and got the bigplayers, and it's just caught up with them this year."

United already face a fight to qualify for the Champions League this season and they will be desperate to get past the Greek side Olympiacos in the final 16 of the competition on 25 February, which is by no means a foregone conclusion.

Keane, however, sees no reason to be overly pessimistic about their future under Moyes. "I think Man United need five or six players. If it happens in the summer then instead of being fearful of it, embrace it – it's exciting. These can be exciting times for Man United. Get them back to the very top where they belong."

United's former captain, now an ITV pundit and assistant to Martin O'Neill at the Republic of Ireland, added: "There's