An Essex Police officer will embark on a charity swim to thank those who helped treat her retired police dog.

PC Karen Pownall, who is based at Canvey Police Station, hopes to raise £500 for the Essex Retired Police Dogs Fund (ERPDF) after the charity helped generate thousands of pounds to heal her seriously-ill pet pooch.

PC Pownall rehomed seven-year-old springer spaniel Kato in March 2014 after he retired from the force.

In his heyday he served county-wide to detect money, drugs and firearms and is believed to be the only Essex Police dog to find a live hand gun.

Six months after re-homing Kato, PC Pownall noticed a big lump had appeared on his hock joint and the vets discovered he had autoimmune rheumatoid arthritis.

The poorly pooch underwent four months of chemotherapy and will be on a dose of steroids for life.

PC Pownall paid for a lot of the treatment herself initially and then the ERPDF offered to pay for the rest, costing about £4,500.

The fund set up a Facebook appeal for Kato during his treatment and donations flooded in over the next 24 hours to cover the full cost of his treatment.

PC Pownall said: “I’ve always wanted to go into the Essex Police Dog Section and I love dogs. I just want to give Essex Retired Police Dogs Fund a bit back because they have been wonderful.

“I’ve always swum since I was a kid and the most I’ve ever done is two miles, so I’m pushing it to three.

“I want to do something that I’ve never done and I’ve never pushed myself that far. It will probably take around two and a half hours.”

Frank Belgrove, ERPDF treasurer, said: “We are absolutely delighted that Karen is raising this money.

“It’s very kind of her and we already have some sponsorship money that has come in for her sponsored swim. She has taken part in other fundraising activities for us too.”

To sponsor PC Pownall’s swim on December 14, visit http://campaign.justgiving.com/charity/essex-retiredpolicedogs/karenswims