Former attorney-general, Dominic Grieve spoke out after concerns that ministers would use a clause in the European Union (Withdrawal) Bill to stop people suing the state if rules on safe pollution levels aren't met, post Brexit.
The Bill will mark the end of the precedence of EU legislation over laws passed in the UK once the country has exited the bloc.
Under the Francovich ruling in 1991, the European Court of Justice established that EU member states could have to compensate individuals or companies harmed by a "sufficiently serious" Government breach of Brussels regulation.
But the EU (Withdrawal) Bill states: "There is no right in domestic law on or after exit day to damages in accordance with the rule in Francovich."
The Conservative MP for Beaconsfield told BBC Radio 4's World At One programme it was unclear what legal options would be available to citizens after Brexit.
He said: "On paper there's a big hole here because on the face of it individuals may well be left far worse off in terms of their remedies against state action than existed previously."
The Bill comes with explanatory notes which state the clause would not affect rights to claim damages already enshrined in British legislation or established by case law.
Campaigners, however, have warned that the clause is so broad that it constitutes a watering down of citizens rights.
Two lawyers told the Times that the Government could use the legislation to avoid its responsibilities concerning air pollution.
A spokesman for the Government said the Francovich ruled is linked to EU membership and, thus, becomes irrelevant after Brexit but the UK "has a longstanding tradition of ensuring our rights and liberties are protected".
They added: "After exit, under UK law it will still be possible for individuals to receive damages or compensation for any losses caused by breach of the law."