Seven incidents were reported across December and January, close to central London but north of the Thames.

The Met Police said the suspect approached the women who, apart from on one occasion, were walking alone, before either exposing himself to them or touching himself inappropriately.

Police described the man as being white, approximately 6ft tall, with a bald head and wearing roller skates.

The incidents took place at the following times:

• 10pm on 26 January on Regent's Canal, near to Oval Road, NW1;

• 7.45pm on 14 January in a tunnel in Goods Way, N1;

• 9.30pm on 13 January in Wapping Woods, E1;

• 12.20am on 7 January in Park Lane, W1;

• 5.20am on 4 January in Praed Street, W2;

• 1am on 4 December in Grove End Road, NW8;

• 2.30am on 2 December in Charlton Street, NW1.

Officers are appealing for anyone who recognises the suspect to call 101 or tweet @MetCC with the reference 7502/26JAN.

Information can also be provided anonymously to the independent charity Crimestoppers by calling 0800 555 111 or visiting www.crimestoppers-uk.org.

Police said anyone who has been the victim of similar offending should call 101 to report the incident.