The scale of population growth in Britain over the next 74 years is to be estimated in figures released by the Office for National Statistics (ONS).
Immigration and increased lifespan are key factors in population rise
The projection of Britain's population up to 2081 takes into account factors including immigration and fertility.
The figures are the first to use immigration estimates that last month the ONS increased by 45,000 a year.
An Oxford University demographics professor has predicted the population will exceed 75 million by 2051.
Eastern European influx
The increased immigration estimates were revealed last month in an ONS document explaining their statistical methods.
It said: "The new long-term assumption for net migration to the United Kingdom is plus 190,000 each year compared with plus 145,000 a year in the previous projections.
"This increase is partly due to taking account of data for two new years - 2004 and 2005 - where net migration to the UK has been at record levels, and partly because of the impact of methodological changes following recent announcements of improvements to the estimation of international migration."
An influx of eastern Europeans whose countries have joined the European Union has contributed to record levels of immigration.
The ONS report out on Tuesday comes days after Oxford University's Professor David Coleman estimated the number of people living in the UK was growing significantly faster than previously predicted.
His estimation of a population of 75 million by 2051 represents a rise by the middle of the century that is six million higher than projections made in 2005.
The current UK population is 60 million.
Population growth will also be accelerated by increased fertility and longevity, according to last month's ONS statistics.