The world's first test-tube baby has revealed the 'sick' blood-splattered hate mail her parents received after her ground-breaking birth.

Louise Brown, 36, was born at Oldham General Hospital on July 25 1978 after her parents Lesley and John became the first people to successfully undergo in vitro fertilisation (IVF).

Her birth attracted controversy, with religious leaders expressing concern about the use of artificial intervention and some raising fears that science was creating 'Frankenbabies', but also paved the way for millions of further IVF births.

She will turn 37 tomorrow and is preparing for the publication of her autobiography, My Life As The World's First Test Tube Baby, next month.

Louise Brown, now 36, was born on June 25th 1978, after her parents Lesley and John (now both deceased) became the first people to successfully undergo in vitro fertilisation (IVF)

Louise's birth at Oldham General Hospital attracted controversy, with religious leaders expressing concern about the use of artificial intervention and some raising fears that science was creating 'Frankenbabies'

Mrs Roberts reveals how her mother received post-bags full of hate mail, including menacing notes, blood-spattered letters, a broken glass test tube and a plastic foetus

In it she talks about how the breakthrough provoked both adulation and revulsion among the public.

Her family received post-bags full of mail, including one package containing letters covered in red liquid, a broken glass test tube and a plastic foetus, accompanied by menacing notes.

Mrs Brown said: 'A parcel arrived addressed simply to "Louise Brown, Test Tube Baby, Bristol, England" it had been posted in San Francisco and the customs sticker on it said it contained a novelty item.

'Inside, mum found a small jewellery-style box with the words "Test Tube Baby" printed on a sticker with an image of some baby footprints.

'She thought maybe it was another gift from a corporate anxious to be associated with my birth but when she opened it there was red liquid that looked as if it had spilled and a carefully folded letter.'

The letter was accompanied by a piece of paper, again splattered in red, with a 'test tube baby warranty card', she said.

There was also a typewritten booklet with 'sick little questions and answers', she continued.

'There was one suggesting that you could keep a test tube baby in a toilet bowl or fish tank,' she added.

'It was menacing and scary and considering the time the people must have taken in putting this thing together then sending it across the world to a three-month-old baby I would say a completely sick act by some sick minds.

'Imagine how worrying this was for mum.

She says her mother also received fan mail and letters of praise. Many letters were from women who couldn't have babies, she added

Mrs Roberts' birth paved the way for millions of couples to have children through IVF. Pictured is a photograph from her autobiography My Life As The World's First Test Tube Baby, out on August 1

Mrs Brown is pictured (left and right) with Professor Sir Robert Edwards, the physiologist who developed IVF treatment, before his death in 2013

'For a while she was even more careful when taking me out in the pram.'

But Mrs Brown, now a mother-of two living in Bristol with her husband, Wesley Mullinder, said the massive media attention surrounding her birth also resulted in fan mail.

She added: 'Many letters were from women who couldn't have babies.

'One woman from Christchurch, New Zealand, wrote with her story of operations that hadn't worked, treatments that had failed and her desire to be a mum.'

Another letter, from Heather Spackman from New South Wales, Australia, read: 'I fear that you will find yourselves on the receiving end of all the usual criticism and condemnation that follows any medical breakthrough, so am writing to try in a tiny way to even things up.'

Her parents were treated by the Bourn Hall clinic in Cambridgeshire as part of the work of Patrick Steptoe and Robert Edwards, who are seen as the pioneers of IVF.

There are now thought to be close to six million IVF babies across the world.

Bourn Hall continues to collaborate with the University of Cambridge and the Wellcome Trust Sanger Centre to develop the science behind IVF.

The book will be published on August 1.