Switching broadband providers will be easier for consumers next year as Ofcom implements new rules to force internet service providers (ISPs) to hand over migration authorisation codes (MACs).

Consumers will now be able to demand a MAC free of charge, from 14 February 2007 as long as they are not tied to a contract. This must be provided immediately or within five working days if it is a written request.

If a consumer complains to Ofcom, the regulator can investigate and if necessary take action against the ISP.

ISPs will also have to ensure the customer's line is untagged; a line tag indicates that a specific telephone line is already being used to provide a broadband connection.

The tag can be left on the line in error or through negligence, such as when someone has moved to a new home and cancelled their service, and blocks a new service from commencing.

BT has also set up a telephone helpdesk on 0800 169 9576 to support those with a tag or marker on their line. It aims to remove these wherever possible, or offer consumers advice where it is not able to remove the tag.

The communications regulator said not being able to get a MAC, which enables customers to switch broadband provider smoothly and with minimal disruption, or getting a line untagged had been a problem for a significant minority of consumers.

More than half of all complaints it received between September 2005 and 2006 related to these issues so it set up a consultation this August to look at the issue.

However, until now the watchdog has not had the powers to force ISPs to hand over MACs.

Although it set up a voluntary code of practice that would give consumers a MAC within five days, few ISPs signed up and many of these failed to stick to the agreement. Some ISPs would charge a consumer around £50 for a MAC

The new rules also take into account the problem of ISPs becoming involved in disputes with their wholesale providers. Now if an ISP is unable to provide a MAC for any reason then the wholesale provider must provide this, no matter what the dispute between the two companies.

A typical example of this type of problem is the V21/Biscit case. The wholesale provider Netservices pulled the plug on the lines it rented to V21/Biscit in a dispute over payments.

The row meant customers were left with no broadband connection or possibility of obtaining a MAC, and the lines were tagged so they could not switch to another ISP.

Ofcom said: "The new rules will also make it the responsibility of all broadband providers to ensure that technical and operational problems such as tag on line do not hinder consumers."

It is still working with the industry, however, to find a way to get MACs to customers whose ISP has gone bankrupt. The regulator told Computeractive it is more complicated getting a MAC in these circumstances.

Overall the move has been welcomed by ISPs. BT said: "We welcome the introduction of the new Ofcom rules on broadband service migration - a development that is good for customers, good for choice and something that helps remove complexity for the industry."

However, the changes will make it easier for consumers to switch and therefore benefit from the increasing variety of broadband packages and services that ISPs are beginning to offer."