Surviving sister Lilian Cox said her twin would "always be in my heart and in my mind".
Read moreTwins
Video content
Video caption: Doris Hobday: Identical twin among UK's oldest dies with Covid Doris Hobday's family say they are "totally heartbroken" to lose her in this way.
UK's oldest identical twins test positive for Covid-19
The UK's oldest identical twins, Doris Hobday and Lil Cox have both tested positive for coronavirus.
Despite, they say, spending most of 2020 inside and sticking to the rules.
The 96-year-old sisters from Tipton posted the news on their Facebook page and urged people to take the restrictions seriously.
Copyright: BBCThey wrote: "We are both in shock... we have been inside for most of 2020 sticking to all the rules and being careful, now this has happened and we can’t work out why or where we’ve picked it up from.
"We are writing this hoping we can save people from getting this horrible virus, please, please, please take this seriously - Covid is real and it’s affecting so many lives across the world... don't let it affect yours or your families [sic]."
Video content
Video caption: Conjoined twins 'learning to stand' for Cardiff school Marieme and Ndeye Ndiaye are making friends and laughing a lot at their new school in Cardiff.
By Lucy Owen
BBC News
By Rebecca Woods
BBC News
Video content
Video caption: Twins joined at head return home after successful surgery Safa and Marwa underwent three major operations to separate their brains.
Video content
Video caption: Twins celebrate 100th birthday Dorothy and Kathleen moved in together at the start of the coronavirus pandemic and turn 100.
By Ashley John-Baptiste
BBC News
By Greg McKenzie
BBC London
Video content
Video caption: Coronavirus: Sister's emotional tribute to twin nurses The sister of twins Katy and Emma Davis, who died of coronavirus, pays emotional tribute.