Google Inc,fresh from losing a bid to buy thousands of patents from bankrupt Nortel,lashed out at its biggest rivals on Wednesday and accused them of banding together to block the Internet giant in the red-hot smartphone arena. In a rare public outburst,Google Chief Legal Officer David Drummond blasted Microsoft,Apple,Oracle and other companies for colluding to hamper the increasingly popular Android mobile software by buying up patents,effectively imposing a tax on Android cellphones. Apart from increasing costs for consumers,snapping up the patents will stifle technological innovation,he said. Microsoft and Apple have always been at each others throats,so when they get into bed together you have to start wondering whats going on, Drummond wrote in a blog post. He referred to a hostile,organized campaign against Android by Microsoft,Oracle,Apple and other companies,waged through bogus patents. Microsoft and Apple had teamed up to acquire patents previously owned by software maker Novell and bankrupt telecom firm Nortel Networks Corp. to ensure Google didnt get them, Drummond added. But Microsofts General Counsel Brad Smith disputed Drummonds version on the Novell patent issue on Twitter. Google says we bought Novell patents to keep them from Google. Really? We asked them to bid jointly with us. They said no, Smith tweeted in response to the blog. Google is forging ahead in the smartphone market. But it has been hampered by a lack of intellectual property in wireless telephony,which has exposed it to patent-infringement lawsuits from rivals like Oracle. It lost out on the Nortel patents to a consortium grouping Apple,Microsoft,Research in Motion and others,which together paid $4.5 billion. Google individually had bid up to $3.4 billion for those patents before teaming up with Intel Corp,which on its own had bid up to $3.1 billion,according to a source familiar with the matter. They bid through $4 billion and then tapped out,another source had told Reuters. The Android software,now used by phone makers including HTC,Motorola and Samsung,has rapidly overtaken Nokia to become the worlds most popular smartphone platform,with about a third of the market. Google,whose crown jewel is its search algorithm,has never placed the same priority on patents as it has on copyright,but is now hoping to stock up. It recently bought more than 1,000 patents from IBM.