Police have repeated their appeal for witnesses to the bus crash that left a grandmother dead and her two-year-old granddaughter in a critical condition.

Elizabeth Panton, 65, died after she and her daughter Sarah Hope, 35, and Pollyanna Hope, 2, were hit by a bus in East Sheen about 9.40am Wednesday.

They had been seeing Mrs Panton off after the group visited her newborn grandson.

Mrs Panton was pronounced dead at hospital.

The mother-in-law of South Norfolk Tory MP Richard Bacon, Mrs Panton had been in Richmond to visit her son, and her first grandson, Rollo, born just days earlier.

Mr Bacon said the family was trying to deal with the tragedy.

"This was supposed to be an incredibly happy day bringing our baby home," Mr Bacon said in a statement.

"Now we're trying to come to terms with all of this."

Pollyanna was taken to Chelsea and Westminster Hospital, where it is believed doctors were battling to save her leg.

This is the same hospital where Mr Bacon's wife Victoria gave birth to Rollo on Monday.

Pollyanna's mother, Sarah, was taken to Charing Cross Hospital, where she was described as stable.

Both remain in a serious but stable condition.

Mrs Panton had travelled from her home in Market Drayton on Tuesday to see her new grandson.

She had been waiting for a bus to take her in to central London, with her family there to see her off.

The accident happened at about 9.48am yesterday in North Worple Way, East Sheen, when a 209 bus hit the pedestrians.

Collision Investigation Unit Sergeant Greg Page said police needed to hear from any more witnesses.

"This bus terminus is in the middle of a residential area with a railway line opposite," Sgt Page said.

"We have some witnesses from the scene but are keen to speak to anyone who was in the area or passing through and may have seen anything of the incident."

A post mortem will be held at Kingston mortuary on Tuesday before an inquest in to Mrs Stanton's death is opened and adjourned.

A man in his 40s has been arrested in connection with the incident.

The 209 route runs from Mortlake to Hammersmith via Barnes.

A spokesman for London Buses said they would co-operate fully with any police investigation.

Any witnesses should contact the Hampton Collision Investigation Unit on 020 8941 9011.