The rise would represent a 3% year-on-year increase and would deliver £8.7 billion additional foreign exchange earnings at today's prices, said VisitBritain.
The extra visitors would help support 200,000 additional jobs, the organisation added.
Launching a consultation on a growth strategy in London today, VisitBritain said it wanted to build on the exposure the UK had from the London 2012 Olympic and Paralympic Games and also showcase Britain's strengths.
These include heritage and culture plus plans to address what VisitBritain described as "perceived weaknesses such as natural beauty, food, value and welcome".
http://www.standard.co.uk/news/uk/visitbritain-plan-huge-boost-to-tourist-numbers-by-2020-8204847.html