Getting your VAT registration certificate can last 14 working days or longer, but your registration date is the one known as your ‘effective date of registration’ and the date from which you will have to pay VAT to HMRC.
It is compulsory to register for VAT if you have more than £82,000 VAT taxable turnover in a 12 month period, if you receive goods in the UK from the EU which are worth more than £82,000 or if you expect to go over this threshold in a single 30 day period.
If neither you nor your business is based in the UK, there is not threshold but you must register if you expect to supply any goods and services to the UK in the next 30 days or as soon as you do that.
Another case when you may also have to register for VAT is if you take over a business that’s already registered in UK.
The period in which you must register from the moment when your business turnover exceeded the threshold is of maximum 30 days. If you are late you still have to pay what you owe from the date when you should have registered.
Voluntary registration is available for business with a turnover below £82,000. VAT needs to be paid in this case from the date the business is registered.
If you think your taxable turnover has exceeded the threshold only temporary, you can write to HMRC with evidence showing it won’t go over the de-registration threshold in the next 12 months and you might get an exception. If you get the exception you will receive a written confirmation of the exception. If you don’t, they will register you for VAT.