Al-jawab billahi at-taufeeq (the answer with Allah’s guidance)
No, it is not permissible.
To partake in Suhur and to delay it until Subah Sadiq (break of dawn) is Mustahab (peferable). (Nurul Idhah Pg. 148)
Prophet (Sallallahu Alaihi Wasallam) said, “Partake in Suhur as there is Barakah (blessings) in it.” (Bukhari & Muslim)
He (Sallallahu Alaihi Wasallam) also said,”There are three habits from the apostles of Allah Ta’ala,
All the scholars are unanimous that Sehri ends upon the commencing of Subah Saadiq (break of dawn) when the horizontal light in the sky appears. Fajr time commences at Subah Saadiq.
Also, It is virtuous to make Niyyah of fast during this time (Subah Sadiq). (Al Fiqhul Hanafi Wa Adillatuhu Vol. 1 Pg. 363)
When the intention of fast is valid:
1) It is virtuous to make Niyyah of fast during Subah Sadiq. (Al Fiqhul Hanafi Wa Adillatuhu Vol. 1 Pg. 363)
2) One can make the intention after Subah Sadiq as long as one did not eat food etc.
3) If you have not eaten food etc, you can make the intention to fast anytime until the Islamic mid-day (Nisfun Nahar Shar’i or Dhahwatul Kubra), which is half-way between the time fajr comes in and when maghrib comes in. [Around an hour before Zuhr.]
4) An intention may be made any time from Maghrib of the night before, and remains valid as long as you did not resolve not to fast. (Aap ke Masai’l Aur Unka Hal Vol.3 Pg. 262)
When the intention of fast is not valid:
1) Making the intention of fast after the Islamic Mid-day, is not valid. (Al Fiqhul Hanafi Wa Adillatuhu Vol. 1 Pg. 363/ Aap ke Masai’l Aur Unka Hal Vol.3 Pg. 263)
Virtues Of Sehri:
Hazrat Anas (RA) narrates that Rasulullah (Salallahu Alaihi Wasallam) Said: “Eat Sehri (food to be taken a little before dawn during the fasting month of Ramadan) that Sehri brings prosperity” (Bukhari, Muslim, tirmizi)
Hazrat Umar (RA) narrates that Rasulullah (Salallahu Alaihi Wasallam) said: “Those who eat Sehri, they are blessed by the angels and Allah the Almighty”
And Only Allah Ta’ala Knows Best.