Sheikh Abdullah bin Mohammed bin Saud al-Thani is looking for British investment opportunities
Qatar is one of the most high-profile investors in London, owning landmarks such as the Shard, Harrods and the Olympic Village, as well as luxury hotels.
It has also sought to diversify its UK investments beyond real estate, including buying stakes in retailer J Sainsbury Plc and Heathrow airport.
The Middle Eastern state said it had committed £5billion of new money to invest in transport, property and digital technology.
Qatar own landmarks such as the Shard, Harrods and the Olympic Village
"I am still looking, even after Brexit there will be opportunities QIA can really hunt for," Sheikh Abdullah bin Mohammed bin Saud al-Thani told an investment conference in London.
Asked what sectors in Britain he was particular looking at, he said: "Our aim now in the future is really to focus on infrastructure, and we will be focusing also on healthcare and IT."
He made it clear that the UK leaving the European Union had little bearing on their decision.
"Over the next three to five years Qatar will invest 5 billion (pounds) in the UK economy through various investment funds and relevant parties in Qatar," he said in a statement released during an investment conference in London.
Qatar has already invested £40bn in the UK – it owns Harrods and a 95% stake in the Shard in London.
It also has a stake in Canary Wharf in the capital's Docklands, as well as an interest in the Milford Haven liquefied natural gas terminal in South Wales.
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The investment will be welcomed by the Prime Minister who is set to trigger Article 50 on Wednesday and formally begin the process of leaving the EU.
It comes as business tycoon James Dyson today spoke of his "confidence" in Britain after Brexit.
The Brexiteer said he was "enormously optimistic" about Britain's prospects outside of the political bloc and said the UK now has the chance to form a closer relationship with the Commonwealth.
He told the BBC: "Europe's only 15 per cent of the global market and the really fast-expanding markets are in the Far East.
"I'm enormously optimistic because looking outwards to the rest of the world is very, very important because that's the fast-growing bit."
Sir James added: "I'm a patriot, which is why I'm rather keen on re-connecting with the Commonwealth."