My mother died 3 years ago. I have been living in her house ever since as we could not sell it. We had it valued for probate and once it is sold will tell the Capital Taxes office of the price so we can pay any further Inheritance tax due. However Will I have to pay Capital Gains please.

There is no inheritance tax involved.
When you sell the property, you may have capital gains. Your cost basis is the fair market value of the property on the date your mother died.
Also, you can exclude gain of up to $250,000 as this is your main home and you meet the exclusion requirements.
If you owned your main home for two years and lived for two years in past five years, then you can exclude gain of up to $250,000. If you are eligible to exclude the gain, you do not report it on the tax return. Your U.S. Tax Return: Profit From the Sale of Your Home

I am sorry I didn't realise that this was an American site I am in England.
Thank you for your time

This is a world site but many of the responders are in the US, and you sound like you are in the US except for 'capital taxes office.' Wait, and perhaps we can get you an answer.