BT and TalkTalk want a judicial review of the Digital Economy Act, saying the controversial new law could infringe "basic rights and freedoms," reports the BBC.

The act – which proposes to disconnect persistent illegal filesharers from the internet – was passed into law in the April wash-up period before parliament was dissolved.

Both BT and TalkTalk are understood to want the high court to clarify whether the act conflicts with existing EU regulation. Ofcom has said plans to disconnect people from the internet would not come into force until next year.

Concerns over "basic rights and freedoms" to access the web are made worse by the manner in which the act was passed into law, BT and TalkTalk say.

The act was "rushed through" parliament with "insufficient scrutiny", claim the internet service providers. After two hours of debate in the House of Commons, the bill was given royal assent – the vote in the government's favour by 189 votes to 47.

Nick Clegg, leader of the Liberal Democrats, said at the time: "We did our best to prevent the digital economy bill being rushed through at the last moment. It badly needed more debate and amendment."

"This is exactly what we and 20,000 supporters warned their MPs," said Jim Killock, executive director of the Open Rights Group. "The Act was rushed through and is already working extremely badly. It threatens basic rights and large chunks need to be repealed."

At present, the act applies to ISPs with more than 400,000 customers – putting larger companies at a commercial disadvantage, says TalkTalk.

Andrew Heaney, executive director of TalkTalk, told the BBC: "It means we could have huge swathes of customers moving to smaller ISPs to avoid detection [from copyright owners]."

Heaney said the act could be in contravention of EU privacy and electronic communications directives, as well as an e-commerce directive stating that ISPs are "mere conduits" of content and should not be held responsible for traffic on their services.

The coalition government, of which Clegg is deputy prime minister, told the BBC it has no plans to backtrack on the act: "The Digital Economy Act sets out to protect our creative economy from the continued threat of online copyright infringement, which industry estimates costs the creative industries, including creators, £400m per year. We believe measures are consistent with EU legislation and that there are enough safeguards in place to protect the rights of consumers and ISPs and will continute to work on implementing them."

Charles Dunstone, chairman of TalkTalk, told The Times: "The Digital Economy Act's measures will cost the UK hundreds of millions and many people believe they are unfair, unwarranted and won't work. Innocent broadband customers will suffer and citizens will have their privacy invaded."

Gavin Patterson, chief executive of BT Retail, said: "We feel we have no choice. We have to do this for our customers."

Ofcom declined to comment.