�I was told that the operation was dependent on intelligence and not all warrants would be successful, but the first raid uncovered a cannabis farm in Squirrels Heath.

Earlier officers had executed the warrant in Fontayne Avenue and discovered 37 cannabis plants and the electricity supply bypassed.

By the time I got to the house at 10am there was a strong smell of cannabis in the street as the door was open.

A bedroom was full of the plants, on the floor and in a wardrobe, with lighting and heating equipment above them.

In a neighbouring room there were more plants. A man was arrested on suspicion of cultivating cannabis and abstracting electricity.

The plants were of different sizes and officers said they were often grown at different stages so the tips could be cut off while others grew.

We returned to the operation base in Jack Brown House, Harold Hill, at 11am where a team of officers was ready to be briefed on their warrant. This was due to be executed in Romford, and Sgt Lee Harding showed the team a map of the area, the house, escape routes, and alleys.

They were shown pictures of the house, of the suspects who lived there, and the vehicles they drove.

They were also briefed about dogs at the property, how many, the breed, and if they were likely to be vicious.

Dogs

Officers discussed the best way in, where they believed the drugs would be and which exits to cover.

We drove to the house and officers wearing protective gear filed out of the police van, ran up to the property and rammed down the door.

After shouting: “Police!” they ran into the property.

Within two minutes the house and shed had been searched and the dogs –Staffordshire bull terriers – secured.

The owners were not at home and drugs were not found.

During the morning there were three other arrests.

Det Ch Insp Phil Rickells said: “The aim is to take out drug dealers and the supply of drugs. The safer neighbourhood teams have been leading this operation with their intelligence and CID has been helping them out.

“We have had some good results this morning, but this is an ongoing operation and we need the help of the community. This operation is not a one-off and the plan is to carry out one warrant a day in Havering.”

Pc Chris Stockman said after the arrest in Fontayne Avenue: “Thirty-seven cannabis plants were found in the house, and that came from good intelligence that we received. It is a good example of the information that the community has given us.”

Anyone with information is urged to call police on 101 or Crimestoppers anonymously on 0800 555 111.

n A man, 24, and woman, 18, were arrested in Capstan Drive, Rainham, for possessing cannabis and a firearms (CS spray). A man, 45, was arrested in Fontayne Avenue, Squirrels Heath, for cultivating cannabis and abstracting electricity. A man, 32, was arrested in Penistone Walk, Harold Hill, on suspicion of intent to supply 13 bags of cannabis, and a 17-year-old youth, was arrested in Hailsham Road, Harold Hill, for possessing cannabis.