It depends...
In 2000 the European Court of Justice ruled that VAT should be levied at the full 17.5% rate on all privately operated road tolls. However, the ECoJ also ruled that, in certain circumstances, central and local government bodies act as public authorities when they operate tolled bridges, tunnels or roads; these tolls therefore remain outside the scope of VAT.
So since 2003 the
M6 Toll and both
Severn Crossings have VAT imposed, but those that do not include;
Cleddau Bridge
Dartford Crossing
Erskine Bridge
Forth Road Bridge
Humber Bridge
Itchen Bridge
Mersey Tunnel
Tamar Bridge
Tay Bridge
Tyne Tunnel
It is advisable to ascertain the VAT status of toll charges whenever you pay them.