Thank you for your question and welcome. My name is ***** ***** I will assist you.
Is this the sort of wording you are after:
1.1 Subject to 1.2 below, X hereby shall indemnify and hold harmless Y against all costs, damages, liabilities losses and expenses (including properly and reasonably incurred legal costs) suffered or incurred by Y arising out of or in connection with [ADD AN EXPLANATION OF THE FACT OR CIRCUMSTANCE THAT IS BEING INDEMNIFIED FOR E.G X's BREACH OF CONTRACT OR X'S FAILURE TO COMPLY WITH A REGULATORY REQUIREMENT];
1.2 Any losses in clause 1.1 shall include but are not limited to any indirect or consequential losses, loss of profit, loss of good will and all interest, penalties and legal costs (on an indemnity basis) and any other direct losses.
If this is only in a letter and not a contract then you will need to ensure that the letter takes the form of a deed or add the following words at the start of the letter:
"In consideration of Y paying X the sum of £1.00 (receipt of which is duly acknowledged by X) X and Y agree as follows:"
I have drafted this based purely on the limited scope of your question, so I must rely on your to make me aware of any other facts you wish to disclose?
I look forward to hearing from you.