What year was building regulation introduced for removing an internal wall?

I sure u wouldn't off needed building regulations to Take down a load bearing wall u would need to employ an architect or structural engineer to work out calculations for the replacement rsj

Building regulations were first introduced in 1936. In 1952 a new set of bye-laws was introduced for all councils to follow. The first set of National Building Standards was introduced in the Building Regulations of 1965, these were a prescriptive standards that had to be followed by all councils. The Building Act of 1984 brought changes to the building regulations. Seek the advice of a Structural Engineer, he will keep you right Hope this helps

You need to check with local authorities for property history. All records should be on file.

As I read this, you are wanting to sell your house, you have had work done in the past, but have no paperwork from buildings regs/structural engineer etc to certify the work, and you are now worried about trying to sell it? I presume you have been filling in your 'property information form' (TA6) and got to the question "Has any building work been done?" and "please provide certificates". Speak to your solicitor, it really isn't a problem, you will just have to take out an indemnity insurance, which the solicitors will organise for you, a Hope this helps.