"But outside the EU, single market membership also comes at the cost of accepting future regulations designed in the EU without UK input"
Yes but it would most likely only apply to those companies who trade with the EU, which is a perfectly reasonable situation - if you want to set up your stall in our market,you follow our rules.
At present every business in the UK has to comply with EU regulations whether they trade with other member states or not.
Also, the reverse would apply. Want to sell holidays in the UK? Follow our rules and register with ATOL
Biting the hand that feeds IT
