Monks from around the country will unite in protest at the Letchmore Heath Hare Krishna temple on Sunday over the execution of a sacred cow.

The RSPCA and a government vet administered a lethal injection to the ill cow on Thursday morning while worshippers were at prayer, despite assurances that no immediate action would be taken.

Cows are sacred to Hindus, and the killing of a cow is considered to be an outrageous act. The killing of a cow at a temple amounts to "religious sacrilege of the worst kind".

Sudarshan Bhatia, head of the Hindu Forum of Europe, said: "Hindu leaders from all over the country are gathering this Sunday.This issue has incensed and united everyone. They are extremely shocked and angry about this and the completely underhanded way it was conducted."

Arjan Vekharia, of the Hindu Forum of Britain, said: "It is quite unthinkable that the RSPCA entered a holy place and killed an animal which is considered by Hindus to be worthy of the greatest care and affection. It is quite outrageous that the priests were lied to."

President of the Bhaktivedanta Manor temple, Watford, Gauri Das said: "We're in a state of shock and disbelief, which is turning into fury within our community.

"Justice should be done. It is so sensitive to kill a cow at a Hindu temple. We deserve an apology at least."

The community are now seeking to get an amendment to the law that would give special arrangements and protection to Hindu cows.

Mr Das added: "Cows should not be killed at our temples, in our community. There are philosophical reasons why we can't kill cows and there should be a special exception in the law. The needs of our community should be considered."

The cow, named Gangotri, a 13-year-old Belgian Blue and Jersey cross, was unable to stand after a "mating accident" in September last year and had been checked by various vets over a long period of time.

Gangotri will now be cremated and the ashes flown to India for a final ceremony at the River Ganges, which it was named after.