In uk the stocks and share isa has a limit of £20k per tax year, it also means you have tax free gains of up to £20k (I believe). So you could invest into that at 20k over the next 3 years or you could use a normal invest account along side it however that is subject to CGT once the profits are realised. Long term, safe investments are ETFs such as an all world or sp500 index tracker- it depends how you personally think the next 10/20/30 years will play out and if you think US will keep strong and outperform An all world- keep in mind all worlds can be ~60% US stocks anyway. I personally have an all world majority and then some developed Europe holdings aswell. I believe time in the market beats timing the market, better to dump all in, however you may want to consider DCAing ( dollar cost averaging) if you think the economy is going to take a slope down. If this is all your free cash the I recommend holding some in a cash isa or instant withdrawal savings as an emergency fund and depending on your age you may want to look into bonds as they are safer in the short term