Moody's has downgraded the bonds of NTL, the UK cable group, by one notch and warned that a second downgrade could follow.

Moody's cut the rating on NTL's bonds from B2 to B3 after a month-long review, initiated amid concerns at the company's $16.4bn (€17.8bn) debt mountain. NTL is using up more than one-third of its revenues to pay its interest rate bills.