The 22-year-old, of Landstead Road, Plumstead, south-east London, was later charged with and admitted supplying class A drugs, being concerned in the supply of cannabis and possessing criminal property.
Police officers working in Radnor Park approached Umukoro after seeing him meeting people they knew to be local drug users.
He was seen throwing a package into a nearby pond, which when recovered, was found to contain crack cocaine and heroin with a street value of up to £1,100.
When searched, he was found to have £1,900 in cash, several mobile phones and cannabis on him. Messages found on the phone showed Umukoro was working for the ‘Rocco’ county line.
County lines is the name given to drug dealing where organised criminal groups use phone lines to move and supply drugs, usually from cities into smaller towns and rural areas.