Police may never know how a newborn baby girl found dead in Rainham died.

The tiny corpse, wrapped in a bin-liner, had lain at the site for “several weeks”, making establishing a cause of death difficult, a police source said.

However, tests will continue.

The body was discovered last Sunday afternoon in bushes by the Ingrebourne River by three 12-year-old boys.

Concerned detectives are continuing to appeal to the mum to come forward.

Det Insp Colin Welsh said: “The baby was newborn and we are concerned that the mother might need urgent medical attention.

“I would appeal to anyone with information to contact us.”

The baby was found with a distinctive pink vest, which cannot be bought in the UK.

A post-mortem examination held at Great Ormond Street Hospital, in central London, last Wednesday was inconclusive.

Officers would also like to hear from anyone who might have seen the bag being left in the undergrowth.

Anyone with information relating to this incident is asked to call 020 8217 6555 or to Crimestoppers on 0800 555 111.