Merseyside, East Midlands, West Midlands and Greater Manchester followed rounding out the “worst five regions” in the UK.
Around 477,000 returns were filed late for the 2017/18 fiscal year, resulting in at least £47.7m in late penalties by HMRC.
In London alone it is estimated that over £10m in late payment fees were collected as 106,000 returns were submitted after the deadline.
Mart Abramov, co-founder and CEO of TaxScouts, said: “Many people dread doing their taxes so much that they will leave everything to the last minute.
“When they do, often they get confused and struggle to understand exactly what HMRC is asking of them, a source of stress and worry for thousands of people in the UK every year.”
He added: “As we approach the deadline for submission, this chaotic eleventh-hour scenario is a cause of stress for a lot of people who need to file a return but just don’t know where to start. Some people don’t even know they have to submit a self assessment and end up missing the deadline because of that.”