Mercedes-Benz is among a number of manufacturers investigating the viability of launching a range of hybrid models combining electric power with diesel engines.

The firm said there are currently no plans for vehicles to launch the system as it is at the development stage, but it is in an advanced stage of design.

A spokesman said there were no plans to put the system in the new S-class, but they were looking at models where its offer of power and economy would be well suited, such as SUVs. Hybrid systems are being seen by manufacturers as the best short-term solution to the environmental demands being placed on transport, particularly the car industry.

Hybrid systems combine a traditional engine with battery power, with the units operating independently or together, depending on driving conditions or the vehicle design.

Currently, only petrol/electric hybrids are on sale, but diesel units are thought to offer the best blend of economy and power.

Already Toyota and Honda have shown that offering a hybrid petrol/electric power system in an everyday car is viable, with their Prius and Civic IMA respectively.

Lexus went one step further this year with the all-new RX400h, which answers complaints about off-roaders being ‘gas-guzzlers’; when it is stopped or coasting, it doesn’t use any fuel.

Most major manufacturers are now looking at developing hybrid units, including GM which revealed a concept diesel hybrid Vauxhall Astra at the Geneva Motor Show earlier this year.

A spokesman for Mercedes-Benz said: "All the manufacturers are looking at this and we are developing the technology, but we do not have a definite decision on which vehicles the system would appear in."