England will become the "world leader" in mental health care for mothers and babies, a leading psychiatrist said, as the NHS announced a multimillion-pound boost for support services.

Pregnant women and those with newborns will be able to access specialist community mental health support in every part of the country by next April, according to NHS England.

Four years ago it was estimated that only 3% of the country had good access to perinatal mental health care.

Dr Alain Gregoire, chairman of the Maternal Mental Health Alliance, said the investment would hopefully "eliminate a long-standing and serious postcode lottery".

He said: "In over 30 years working for the NHS I have never seen any national programme produce such a rapid, effective and widespread transformation in services.

"These new, top quality services have led directly to life-saving improvements in care for women and babies that will hugely reduce immediate and long-term suffering.

"The new developments announced today in England look set to eliminate a long-standing and serious postcode lottery, and will undoubtedly make England the world leader in mental health care for mothers and babies."

One in five women will experience a mental health problem during their pregnancy and in the first year after birth, most commonly depression and anxiety disorders, experts say.

The new £23 million roll-out builds on £40 million spent on 20 sites in 2016 to establish or expand community mental health services across the country.

More than 7,000 mothers have accessed treatment so far.

It is hoped the overall package of measures, worth £365 million, will help more than 30,000 additional women access care by 2021.

The NHS also plans to open four mother and baby units, each with eight beds, during 2018 and 2019 to provide support in areas of the country where access has traditionally been difficult.