Complex sentence: The toll is indeed collected on the English side, and only on vehicles travelling westwards from England to Wales, leading some people to describe it as a "tax on entering Wales", both in jest and also as a more serious anti-toll campaign.
Split into simpler sentences: The toll is indeed collected on the English side, but only for vehicles travelling westwards from England to Wales. This has led some people to describe it as a "tax on entering Wales", both in jest and also as a more serious anti-toll campaign.