The UK has the highest prison population in the European Union, according to a major new report.
There were a total of 95,248 people behind bars in this country, figures published by the Council of Europe show.
Of the 50 prison administrations examined in the study, only Russia and Turkey had more inmates, with 671,027 and 151,451 respectively.
The study, which covers a period up to 2014, also claimed that only Russia spent more on its prisons system than England and Wales.
In September 2014 there were 85,509 prisoners in England and Wales, 7,879 in Scotland and 1,860 in Northern Ireland.
It was the largest total out of all the 28 EU member states. The next highest population in the bloc was France, which had 77,739 inmates, while there were 65,710 inmates in Germany.
England and Wales had a higher-than-average prison population rate, according to the study, with nearly 150 inmates per 100,000 residents. Between 2005 and 2014, the rate rose by 4.9% in England and Wales, by 30.7% in Northern Ireland and 10.7% in Scotland.
The rates in France and Germany were 118 per 100,000 and 81 per 100,000 respectively.
Lead researcher Professor Marcelo Aebi said of the prison population in the UK: "It is high and it is not improving.
"It could be reduced. Look at the length of sentences."
The UK had some of the highest proportions of inmates serving life, researchers found, with lifers accounting for 10% of inmates in England and Wales in 2014, compared with an average of 3%.
The Council of Europe's annual report on penal statistics said the total spending on prisons in England and Wales was 3.3 billion euro in 2013 - £2.6 billion at today's exchange rates. Only Russia had higher costs at £4.9 billion (6.4 billion euro).
Researchers also compiled figures for the average amount spent per inmate per day in 2013.
In England and Wales this was £85 at current exchange rates (110 euro).
This compared to an average across all nations of £77 per day (99 euro), and was also higher than in France, which spent £78 (100 euro), but lower than Germany (£87/112 euro) and Italy (£100/130 euro).
Costs ranged from 2.68 euros per day in Ukraine to more than 200 euro per day in countries including the Netherlands, Norway and Sweden.
Shadow prisons minister Jo Stevens said: "These shocking figures reflect what we have repeatedly said to the Government; our prisons are overcrowded, understaffed and at breaking point.
"The social and economic cost of our prison crisis will continue to increase if we do not tackle head on the underlying failures presided over by this Government. "