Say you've won about £50,000 and you want to only invest with your money....?

Question

Which institution do I trust with my money to allow me to buy and sell (and short) at any time I please? stock broker, building society, etc. (I'm very young so dividend income is not a priority at all + I'll enjoy the risk)

Answer 1

If I won that kind of money. First I will put 1/5  to earn interest. 1/5 in Mutual Fund and the rest on the stock and option trading.

Currently I am trading option on the thinkporswim plate form. It is a real time  trading online broker. May be you can try it first and see how does it work out.