Suspected LulzSec members Ryan Cleary and Jake Davis have pleaded guilty to involvement in attacks on several high profile agency and company websites, according to the BBC.
The two admitted to the offences in court on Monday, but Ryan Ackroyd and the other unnamed 17-year-old suspected member were both reported to have pleaded innocent to the charges.
A Crown Prosecution Service representative stated that they could not confirm or deny the suspects' pleas when contacted by V3.
The campaign saw the group target several high profile organisations and companies including the UK's Serious Organised Crime Agency (Soca) and the Rupert Murdoch owned News International.
Other suspected high profile LulzSec victims include the NHS, Sony, Nintendo and 20th Century Fox.
American law enforcement is also mounting a case against Cleary, accusing him of breaking into and defacing several US company websites.
Prior to the trial Cleary had been held on remand after breaching his bail conditions by contacting the former leader of LulzSec Hector Xavier Monsegur - aka Sabu. Sabu was himself revealed to be an FBI informant earlier in 2012.