But a Safe and Sustainable spokesman said: "We are advised by our lawyers that the CHSF's alternative proposal is unworkable and would disrupt the process of implementation across England.
"Whilst we regret the CHSF's stance and its attempts to disrupt the national process of implementation through legal challenge, we stand ready to defend our process and our decision with confidence."
"Our response to CHSF
's lawyers will be issued in the next few days and will address the points raised by the CHSF
today following careful consideration".
The Children's Heart Surgery Fund (CHSF
) is stepping up its bid to save the unit and supporters believe Option E would mean patients would face reduced journey times, give the provision of high quality care and deliver multiple services under one roof and be easily accessible.
And the team behind the Children's Heart Surgery Fund (CHSF
) will take over the outside area of the Leeds City Museum at Millennium Square to highlight their campaign.
Representatives from the Children's Heart Surgery Fund (CHSF
), young heart surgery patients and their parents arrived at Downing Street in an ambulance before handing over the petition at Number 10 yesterday.