Dyson, maker of the famed bag-less vaccum cleaners and blade-less table fans is facing a counter-suit by Bosch alleging the UK company had made ''false'' claims about its vacuum cleaners.
Sir James Dyson last week claimed that Bosch had been making misleading claims regarding the energy efficiency of some of its appliances, as his company took the German firm to court
(See: Dyson accuses Bosch, Siemens of Volkswagen-like acts).
''Bosch has installed control electronics into some of its machines to cheat the EU energy label,'' he told The Telegraph.
In his allegations Sir James claimed, the AAAA energy rating achieved by some of Bosch's vacuum cleaner models was only achievable during lab tests.
According to BSH Hausgeräte, manufacturer of home appliances under the Bosch and Siemens brands, the allegations were ''unfounded and untrue''.
"We have long since been aware that James Dyson has a history of taking a very aggressive approach against his competitors and has a desire to be in the public eye,'' said BSH chief executive Karsten Ottenberg.
''With his completely unfounded accusations of cheating in the past week he has now overstepped the mark, which is why we will now initiate legal steps against Dyson.''
According to Dyson, its lawyers were not aware of any legal claim by BSH.
Dyson claimed that independent testing had shown that machines made by Bosch and Siemens could draw over 1,600W of power when used in the home, despite having a rating of 750W.
The UK company had initiated legal action against BSH in Germany, the Netherlands and Belgium on the basis that it misled consumers.
BSH said it showed a year ago that Dyson's energy consumption figures on labels for its appliances were incorrect.
In its defence, BSH said its vacuum cleaners were fitted with sensors designed to maintain suction as the bag filled up. It added this loss of suction was ''one of the main challenges'' for bagged cleaners and that it fitted the sensors in 2013 before the EU energy label was introduced in September last year.