Kent Police have issued an appeal after the incident, said to have happened around 3pm on October 31.
A Kent Police spokesman said: “A woman was walking in a wooded area between Tea Garden Lane and The Midway when she noticed a man carrying out an indecent act.
“As the victim tried to walk away the man is said to have then followed her whilst still exposed. He is described as white, aged between 40 and 50 and with blond hair. He was wearing a grey and orange top, possibly a fleece.”
Police are urging anyone with information to come forward. Officers would particularly like to speak to two women who the victim saw as she was leaving the area and who may have important information.
Local residents with fixed CCTV cameras are also being asked to check and report anything suspicious.
If you can help, contact the west Kent appeals line on 01622 604100, quoting reference YY/39561/18. Alternatively, contact Kent Crimestoppers anonymously on 0800 555 111.
