Roberto and Jesús María Moreno Ramírez, from the region of La Rioja and aged 40 and 44 respectively, were flying to the UK capital via Frankfurt (Germany) from the Dominican Republic.

They were detained by border force staff at T1 after their 'unusually heavy' suitcases were X-rayed and turned out to have false bottoms, according to the British embassy in Madrid.

Border officials tested the three kilos of white powder found packaged inside hidden compartments in their cases and revealed that the contents was uncut cocaine, with a UK street value of 300,000 pounds sterling (around 360,000 euros).

They are said to have pleaded guilty to importing Class A drugs and were sentenced on Thursday by Isleworth Crown Court.

Peter Avery, assistant director of the border force agency said the verdict reflected the fact that this 'significant' quantity of cocaine had 'potential to do a lot of damage'.

He added that the brothers' jail term was to 'serve as a warning' against 'dangerous drugs' being trafficked and 'making it to UK streets'.

According to Avery, the border force team is 'on constant alert' to prevent such offences.

The embassy has urged anyone in possession of information that could lead to the arrest of drug-smugglers to call the British border authorities on (0044) 800 59 5000, which is free of charge if dialled from the UK.

Photograph 1: London's Heathrow airport, Terminal 1 arrivals, where the men were caught

Photograph 2: Roberto Moreno Ramírez, 40

Photograph 3: Jesús María Moreno Ramírez, 44