Police caught a man in the act of stealing diesel from a HGV parked on the A1 at Colsterworth.
Ramunas Bruzaitis, speaking through a Lithuanian interpreter, admitted stealing diesel on May 4.
The 24-year-old from Lilac Close, Wisbech, was spotted by police standing beside an Audi at the junction with the A151 at 4.40am.
The police officers spoke to Bruzaitis and noticed a strong smell of alcohol on his hands.
Nearby were three containers - which also smelled strongly of diesel - one of which had a pipe running from the container to the fuel tank of the HGV.
Daniel Pietryka, defending, said: “The driver was in the HGV having a rest and clearly unaware of what was going on.”
Rob Arthur, defending, told the court Bruzaitis said the diesel was for his own personal use.
Bruzaitis was fined £75 and ordered to pay costs of £85 and a £20 surcharge.
Mr Arthur said Bruzaitis’ outgoings exceed his income “which may well be one of the reasons he committed the theft”.
He added: “Clearly he is going to have to curtail his lottery and other expenses to ensure this is paid as a priority.”