The EU Single Market exists to protect inefficient EU businesses from external competition - but it is not entirely the EU businesses who are at fault for their inefficiency.
Much of the inefficiency - and so over pricing - is due to EU red-tape and over-regulation. In decades when IT and tech should have been streamlining business 'business at the speed of thought' - the EU have been soaking up any such efficiency gains with evermore pointless regulation - much of which was then gold plated by the UK's own politicians/mandarins when being implemented here in the UK.
Leaving the EU gives us back control or our laws and trade and borders - but we will only benefit from this when the newly returned control is actually used to strip away the many, many layers or anti-competitive, bureaucratic red-tape, controls, directives, standards, that needlessly drag on EU companies.
Unfortunately, Theresa May has indicated that she is to do exactly the opposite of this - she has said that all EU law (over 200,000 pages of it) will be transferred wholesale into UK law, immediately added to - and then over many years is expected to be gradually reviewed.
This will kill the UK - we will have floundered and drowned before even a tiny fraction of the baggage has been removed, it will drag us down.
To get the benefit of Brexit, the UK must have a lean and agile economy - an economy as dynamic, flexible and imaginative as the people of the UK have always been when the state has got out of their way.
Theresa May must be made to change her mind - so by default all EU law should cease on Brexit. Only specific, new, necessary law, compatible with the UK's system of justice should be created - we have two years to specify this law, ready to come into force when Brexit is complete on the expiry of the Article 50 notice period. But this change of mind must be rapid, as time will run out if it is not started ASAP.