I'd split it to create a diverse portfolio of investments, some high risk high return, some low risk but long term. If I couldn't get a return exceeding the cos

I'd split it to create a diverse portfolio of investments, some high risk high return, some low risk but long term. If I couldn't get a return exceeding the cost I'm paying on the mortgage, I'd put the cash into the mortgage to lower my outgoings, then take the difference and invest that instead. The rationale behind that approach is that you'll save money by not paying interest, the amount you save is largely dependent on what you owe and the interest you're paying, but you're probably paying more mortgage interest than what you'd get out of most savings. I'd also buy some precious metals (Gold, Silver etc.) and a safe. Not a gold bug, but it'd be good to fall back on if I need the funds, plus it will appreciate over time.