Here are the new rates from 1 December 2013 which show a reduction in most situations as under with the previous rates in brackets where a change applies:

engine size petrol diesel LPG
1,400 cc or less 14p (15p) 9p (10p)
1,600 cc or less 12p
1,401cc to 2,000cc 16p (18p) 11p
1,601cc to 2,000cc 14p (15p)
over 2,000cc 24p (26p) 17p (18p) 16p