Written prescription fees from vets will be capped at ยฃ21 as part of a raft of changes that practices will be legally required to bring in over the coming months.

Vets must also tell clients if cheaper medicine is available online, write price estimates ahead of treatment, and publish price lists for services as part of the rule updates.

The official competition watchdog has brought the measures into force after its investigation into the sector found prices had been rising at nearly twice the rate of inflation.

However, critics say the measures will hit independent vets hardest and will benefit the six firms that own more than two-thirds of practices.

The Competition and Markets Authority (CMA) made its remedies for the sector legally binding as of Tuesday and vets have up to 12 months to bring all the changes in.

As well as capping prescription fees, other changes include:

Vet practices must publish a "comprehensive" price list for standard services โ€“ including consultations, common procedures, and cremation options

A written estimate must be provided in advance for any treatment expected to cost ยฃ500 or more, including aftercare costs, plus an itemised bill. Emergencies are the only exception to this

Vet businesses must make clear whether they are part of a group or an independent business

To help pet owners compare local practices, price and ownership information will be made available through the Royal College of Veterinary Surgeons' "Find a Vet" service, which will share the data with third-party comparison sites.

The timelines for when vets need to bring in the fixes depends on the exact regulation and the group's size. The CMA sets it out here., external

"The changes that are being required are changes that will help inform pet owners about prices," said CMA panel chair Martin Coleman.

Cate Titterton believes vets will have to put up prices for things like consultations and surgeries

However, Cate Titterton, the owner of an independent vet service in Saltburn, told the BBC the changes will make trips to the vets more expensive for customers.

"Veterinary practices still have to have a pharmacy that is fully stocked, so if we're not making that tiny profit on the drugs, we're going to have to make some profit elsewhere.

"So, things like services, consultations, surgeries โ€“ unfortunately, those prices are very, very likely to have to go up."

She believes there is "one clear winner" from this - larger vet groups and the corporates.

File on 4 Investigates: What's Happening to Your Vet Bills?

Cat Henstridge, another vet, said it was "wonderful" that businesses must now make clear if they are part of a large group, but noted that such groups "have not actually been asked to change their ownership of any clinics or anything like that".

Speaking on the Today programme, she advised pet owners who are worried about the cost of care to "be open and honest with your vet about what is affordable for you".

"There is always going to be a bill. Veterinary medicine is private medicine. Owning a pet does come with the responsibility of paying for their care.

"[By] working with us, we can make it work for you, but you have to tell us about it first," she said.

British Veterinary Association President Dr Rob Williams said veterinary practices were already largely working to the CMA's remedies, including the orders relating to complaints handling, price estimates for routine procedures and prescription costs.

"We've been clear with the CMA throughout its investigation that it must ensure its remedies do not disproportionately impact smaller, independent practices and we've pushed back where we've had concerns," Williams said.

Clive Di Giorgio says he was quoted thousands of pounds for cancer treatment his dog Louis didn't need

One person hoping to see a cheaper more transparent market for vet services is Clive Di Giorgio, who got in touch with BBC Your Voice.

He says he was quoted thousands of pounds for treatment after a vet told him that a rash on his dog Louis' back was "definitely" a sign of cancer.

However, after going to a different vet surgery, he says he was told Louis' rash was not cancerous.

A treatment of steroids, antibiotics, and a spray cleared up the rash in two weeks, Clive says.

"You just don't feel as if when you go to the vets now they're interested in the animal," he says.

"You feel as if all the interest is how much money they can basically squeeze from you."

How have vet charges affected you? Do you welcome the changes?

Vet prescription fees to be capped at ยฃ21