Tusk, the president of the European Council said the chances of Brexit being called off were rising due in the main to the fact that in his view the British public would reject leaving the EU in a second referendum.
The EU's most senior official believes that if Britain voted again today then the outcome of any IN/OUT referendum would be different to that of June 2016.
Tusk believes Remain would win the second vote because British voters had only really realised the impact of Brexit after the first referendum had taken place.
"A real debate about the consequences of Brexit wasn't had during the referendum campaign, but only after the vote. Today the result would probably look different. Paradoxically, Brexit awoke in Great Britain a pro-European movement," Tusk told Polish newspaper Gazeta Wyborcza, in an interview shared with other European newspapers.
"The referendum was at the worst possible moment, it is the result of a wrong political calculation," he added, in a reference to former PM David Cameron's decision to offer voters a referendum as part of his 2015 election manifesto.
"After the British referendum in 2016, I thought that if we recognise that the case is closed, it will be the end. Today the chance that Brexit will not happen is in my opinion 20 to 30 percent. That's a lot," he said.
"From month to month, it is becoming increasingly clear that the UK's exit from the EU will look completely different than the Brexit that was promoted. I see no reason to capitulate," Tusk said.
"Even if we repeat that the referendum is the expression of will by the nation and the will of the nation must be respected, yes, you have to respect it," he said.
"But the 2016 referendum was not the first on the UK's membership of the EU. The first was in 1975 when the British, two years after entering the EEC, decided to remain in it.
"If the 2016 referendum was able to change the result of the 1975 referendum, why can it not be changed again? Nothing is irreversible until people believe it is."
Talks between Theresa May and Labour leader Jeremy Corbyn to find a deal that can be put to parliament appear to have stalled.
This week Corbyn, who has been reluctant to back a second referendum, said a re-run of the vote could act as a "healing process".