I have accidently deleted ibdata1 on an ubuntu server
As you probably know, you've deleted your InnoDB data file. Your options are basically to restore from backup if you have one, or hire a data recovery company with MySQL knowledge to see what they can salvage off the disks. Some of the MySQL consulting firms like Percona and Pythian might be able to help you there, but it won't be cheap, and they might not be able to recover much. If you want to try recovering the deleted file, stopping all write activity on the filesystem that held ibdata1 or remounting it read-only as soon as possible will increase the likelihood that someone will be able to retrieve anything.