But high costs look set to prevent the ultimate-economy 307 and C4 hatchback models from going on sale until at least the end of the decade.
Powered by 1.6-litre HDi turbodiesel engines linked with electric motors and stop-start systems, the cars return a record 83-plus mpg in urban driving conditions – 25% better than petrol-driven hybrid models of similar size – with exhaust emissions of 90g/km.
When PSA Peugeot Citroen previewed the models in Paris, a spokesman said: ‘They could be in production tomorrow, but the cost of the technology they use is too expensive.
‘Our big job now is to cut this sufficiently to make them commercially viable.
‘A premium of about £2,000 would need to be charged if these cars went on sale right away.
‘That’s double the amount most people expect to pay for diesel power over the price of petrol and our target is to reduce it by half.’
PSA has asked the French government to support extensive research into trimming the cost of the high-voltage batteries, electric motor-generator, inverter and regenerative braking system that back up the 90bhp diesel engine used in its cars.
The hybrid models, which feature a particulate filter system and have electronically-controlled manual transmission, allow speeds of up to 31mph to be reached in all-electric, zero-emission, mode – and are thought to be unique in guaranteeing mobility even when their battery packs are completely run-down.