Yorkshire Tea has apologised after receiving complaints about “misbehaving” biodegradable tea bags which have left some customers stewing.

The apology follows criticism that plant-based tea bags, which were introduced earlier this year, have been splitting, leading to spoiled cuppas.

Responding to the claims, Yorkshire Tea said the problem has only affected a small proportion of bags, but added: “People are used to our tea bags being reliable, so it’s a big deal when they go wrong.”

A spokesman said: “Some of our tea bags have been misbehaving. If it’s happened to you, we’re really, really sorry.”

The tea-maker started the process of switching over to the renewable, plant-based material for the bags in October.

Yorkshire Gold bags have already made the switch, and Yorkshire Tea is part-way through the changeover.

“The new tea bags have been brilliant in our trials,” the spokesman added.

“Now they’re out in the world at a much bigger scale, some of them have been splitting while brewing.

“We’re gutted to be letting people down. We don’t think it’s all down to the material – we think there’s more technical work to be done to make sure it’s working properly with all of our tea bag machines.”

The tea-maker said it would resume “testing and tweaking” on the new bags, adding that it also hopes to have fully carbon neutral products by this time next year.

Among those complaining about the new bags was football pundit Darren Fletcher, who tweeted: “Shocking developments this morning in the Fletcher household – the normally reliable & excellent @YorkshireTea (Gold) is shambolic.

“Every tea bag we have used has split. Dodgy box I reckon or is it new paper? Things may never be the same again!!!!”

Responding on social media, Yorkshire Tea said: “Yikes – sorry Darren! Yorkshire Gold has switched to biodegradable bags, replacing the oil-based plastic that used to seal them.

“It’s early days so we’re very keen to hear feedback. Fancy telling our customer services team at hello@yorkshiretea.co.uk so they can put this right?”

One Twitter user joked that the problem was causing “much moodiness in the morning”, while another said: “I’ve been drinking your tea the last month or so (having been a Tetley drinker all my life) and I really enjoy the taste… what I don’t enjoy is the number of split teabags that I’m getting. Every third or fourth bag splits.. what’s that about?”