what would you do with it to maximise its value and minimise the risk of losing it?
These two statements are very contrarian to each other, as often increasing a risk premium comes with increasing returns.
Some others have given good suggestions.
My first belief in this current financial environment is wherever possible you should pay down debt you have at any cheaper rate, e.g. overpay a long term fixed mortgage you have before you have to refinance. The era of ultra low interest rates is gone IMO and so this is most wise.
If it is a safe environment you want for your money (while accepting there are no 100% certain things in life), then a cash savings or cash isa account should yield a 4% return. Cash isas come with tax benefits, but amounts are limited to £20k per year, standards savings do attract tax after £500 or £1000 interest, depending on your tax bracket.
A lot of people don't factor in inflation, remember that is eating away at everyone's savings while it remains high. Currently no savings account of note is paying more than the inflation rate, so everyone with savings is losing spending power in the economy, i.e. their savings are eroding.
As you take more and more risk you can potentially generate more return, but you really should get financial advice on these sort of matters, and then consider often this advice isn't a golden bullet to wealth.
Your time horizon is also key, any investments you should have a longer term time horizon, 5 years+ and you should consider whether you want your assets liquid (such as cash) or illuquid, (such as property).
You would also be wise to have a balanced range of savings and investments. An emergency fund where you could expense your life for 6 months worst case that is highly liquid, then a range of financial products in different areas.
Also please consider the capital gains taxation system is changing in the UK, so that is another factor to consider.
Personally to me on £50k I have a high tolerance to risk and it wouldn't bother me to lose it. I would of hedged a large portion of it on gold and silver and would trade derivatives. I'd base what to trade on a lot of macro economic research and on quite short term market sentiment. I returned 47% on my money last year, a lot of the time by shorting markets, but I fully accept eight in ten people who trade in this way lose money and often quite quickly and I could easily be one of them. If I trade in this way I use leverage, stop losses and take profits with the broker to then trade again. But I strongly believe this isn't wise for most people.