Private companies have paid out massive dividends to shareholders - money that could have been invested in the network, the RMT union said.
Its comments came on the eve of the 20th anniversary of the passing of the Railways Act on November 5 1993 - legislation that paved the way for the privatisation of the railways.
RMT general secretary Bob Crow said there had been "two decades of greed, exploitation and political sabotage" which had "dragged Britain's railways through the mud in the name of private profit".
The union said:
:: Private train operators and rolling stock companies paid out dividends of over £359 million in 2012/13 alone;
:: Since 1995 more than £3.5 billion has been paid out to private train operator shareholders in dividends;
:: Average ticket prices have increased by over 23% in real terms since 1995 "leaving us with Europe's highest commuter fares for both day returns and season tickets";
:: Rail passenger fare revenue in the UK increased 150% between 1994-95 and 2012-13 "while investment has been effectively frozen";
:: There has been a halving of track access charges, the money the private train companies pay Network Rail to use the infrastructure, from £3.19 billion in 1994 to £1.59 billion in 2012;
:: Overseas companies, mainly state owned, now control 65% of Britain's railways "proving that the Government are happy with state ownership as long as it's not by the British state in the interests of British people".
Mr Crow said: " British passengers are now paying the highest fares in Europe to travel on overcrowded and unreliable services that have been starved of investment.
"For 20 years the political class, of all parties, have failed the British rail passengers and workforce while overseas state operators have been allowed to plunder our services to keep costs down on their own turf."
However, a spokesman for Rail Delivery Group, the rail industry body, said: "The RMT's figures are totally misleading. Almost twice as many passengers are choosing to go by train as in the mid 1990s.
"Meanwhile, money being returned by train companies to government has quadrupled to £1.7 billion last year alone and margins remain, on average, 3%. Significant investment and an industry focused on attracting more rail users are delivering for passengers, businesses and taxpayers."
A Department for Transport spokesman said: "The independent Brown Review into rail franchising was clear that franchising remains the best way to secure services for passengers.
The UK's railways were privatised in the 1990s and this Government has no plans to renationalise them at huge expense to the taxpayer.
"To continue the success of franchising, the Government is committed to delivering fair and open franchising competitions to find private companies that will provide the best possible deal for taxpayers and passengers.
"A strong private-sector partner provides certainty of ownership for franchises and delivers benefits to passengers and taxpayers for years to come."