I'm looking at remortgaging but looking through my current mortgage details I have something called an early repayment charge (ERC). What is this for? Is it fair that I can get charged for wanting to change mortgage provider?

An early repayment charge is a fee charged by your mortgage lender for repaying your mortgage earlier than you had originally agreed.

Most mortgage deals come with an ERC. For example, if you have a 2yr fixed deal, the majority of the time you will be tied in for 2 years and if you want to leave before the 2 years is up then you have to pay the ERC.

This should have been made very clear to you before you signed up for the mortgage. It is one of the downsides to the longer mortgage deals (ie 5 yr fixed deals or 5 yr trackers) but if you want a deal with no ERC you will generally pay a higher rate/fee.

Did you obtain your mortgage through a mortgage broker? A good mortgage broker should explain all of the aspects of your mortgage to you and make sure you understand exactly what you are signing up to. If you got the mortgage direct from a bank, they should have explained this to you. It will definitely be detailed on the Key Facts Illustration that will have been provided to you before you took out the mortgage.