Channel 4 has signed up to provide programmes for the streaming service BritBox, the Guardian understands, meaning shows from all the UK’s main television channels will be available through one catch-up outlet for the first time.

BritBox, which is due to unveil its launch plans on Thursday, is being pitched as an additional streaming service for viewers who want to view classic British television programmes and films, rather than as a direct competitor to Netflix. It will be priced at £5.99 a month, cheaper than rivals, with its backers hoping to capitalise on the interest in family viewing in the run-up to Christmas.

The deal will mean it is the first time that all the UK’s traditional channels have managed to successfully bring together programmes on a single streaming service, enabling viewers to watch archive content from the BBC, ITV, Channel 4 and Channel 5.

BritBox was founded as a joint-venture between ITV and the BBC, although the commercial broadcaster is taking the lead and owns most of it. The service had already announced the addition of parts of Channel 5’s back catalogue – including the Bafta-winning Cruising with Jane McDonald – plus material from Comedy Central.

Until now, Channel 4 had been a holdout, but it is understood the broadcaster has agreed to provide programmes to the service, including material from its Film4 arm and recently broadcast shows. Channel 4’s shows will join the service early next year.

BritBox has already launched in test mode with a limited range of programmes, including classic comedies such as Absolutely Fabulous, The Thick Of It and Only Fools and Horses.

It offers many boxsets ranging from ITV’s Brideshead Revisited to recent BBC dramas such as McMafia, plus classic British films including more than a dozen from the Carry On series. Programmes can be searched by actor, bringing together shows by the likes of Keeley Hawes and Olivia Colman in one place, regardless of the channel on which they were originally broadcast.

Many programmes are also available on existing streaming services such as Netflix, but “BritBox exclusives” not available elsewhere include Wolf Hall and the Martin Clunes series Manhunt.

BritBox member channels will continue to run their own catch-up services. The BBC recently won permission to keep most of its shows available for free on iPlayer to licence fee payers for up to 12 months, after which point many programmes are expected to transfer to Britbox.

The launch comes a decade after the competition authorities blocked proposals to launch a similar service called Project Kangaroo, which was intended to become a one-stop shop for all British online television streaming. That decision forced traditional public service broadcasters to prioritise their own catch-up services, and is blamed for helping Netflix to dominate the UK market.

Spokespeople for Britbox and Channel 4 declined to comment.