George Osborne's new tax rules would have forced Man Utd to pay Corporation Tax

The Chancellor's new rules that limit debt interest relief are bad news for any investor who has bought a British company using lots of borrowed money.

The Glazers' purchase of Manchester United in 2005 was one such deal, loading the club up with so much debt (£411m as of last results) that, in recent years, servicing it has wiped out profits - much to the understandable annoyance of fans.

Last year was no exception. As you can see from the club's results the £35.4 million Man Utd spent financing its debt turned a profit of £31.2m into a loss of £3.9 million - one which won the club a Corporation Tax credit of £2.8 million.

Under the new rules, only 30% of Man Utd's profit for last year (£31.2m) would have been eligible for debt interest relief. The cap in this instance would have been £9.3 million.

Last year £35.4 million of debt interest relief was claimed, so £26 million would be disallowed under the new regime.

I've just chatted to Richard Murphy of the Tax Justice Network - an accountant of the chartered variety - who calculates that the new rules would have left the club more than £5 million worse off. Instead of a tax refund of £2.8 million, the club would have paid a Corporation Tax bill of £2.4 million.

The changes the Chancellor made to debt interest relief today brings the UK in line with the OECD's recent recommendations. Germany, Italy and Spain already have similar standards. The impact will be felt well beyond Old Trafford and well beyond football.

Any club that is heavily burdened with debt (step forward Liverpool, Chelsea, Man City) is likely to pay tax differently. More generally and more interestingly, it strikes me that the changes make it harder for large investors to borrow aggressively and buy profitable British companies.

Saddling successful companies with debt has become a common financing structure in recent years (look at the takeovers of the AA, Boots and Cadbury's). Many would argue that making these deals less easy to do is a rather good thing.