Over a million people face a £100 penalty for having missed the January deadline for Self Assessment forms says the Inland Revenue.
More than three million have missed the deadline since the system was introduced in 1997.
There are still 350,000 returns still outstanding from January1998 and the Inland Revenue has sent out at least 20,000 penalty notices by mistake.
Former tax inspector Peter Back, of on-line tax service Virtuallyanywhere thinks the Inland Revenue will have to consider an amnesty for people who miss the deadlines.
He says: “This would allow non-payers and tax evaders time to pay their tax before a harsher penalty regime is introduced.”