The Internet Service Providers Association (ISPA) has said government proposals that require ISPs to block porn-based websites will not be feasible.

Nicholas Lansman, the secretary general of the ISPA, said: "blocking lawful pornography content... will lead to the blocking of access to legitimate content and is only effective in preventing inadvertent access".

"Online safety is a priority issue for the internet industry and ISPA will be discussing the options available to protect children with government."

Lansman added the ISPA firmly believes that controls on children's access to the internet should be managed by parents and carers with the tools ISPs provide, rather than being imposed top-down.

Culture minister Ed Vaizey revealed yesterday is to meet with ISPs including Virgin Media, TalkTalk and BT "in the near future" to discuss the plans.

"This is a very serious matter. I think it is very important that it's the ISPs that some up with solutions to protect children," Vaizey told The Sunday Times.

"I'm hoping they will get their acts together so that we don't have to legislate, but we are keeping an eye on the situation and we will have a new communications bill in the next couple of years."

A spokesman for the Department for Business, Innovation and Skills (BIS) confirmed Vaizey intends to dicuss the plans with ISPs. However, he added: “there is no confirmed date yet and we are currently in the process of setting this up”.

The proposals, which follow moves by UK ISPs to block access to all websites containing child pornography images, also include the ability to 'opt in', which means web users will have to request access to specific sex-related sites.