Interestingly if this Southend comes off, it could make a return to the days of 3 scheduled London links.
The BA Cityflyer 'base' is also proposing a 1 weekly LCY flight to position the aircraft back to its weekday base, LCY-MAN on Thu and MAN-LCY on Sun.
While the latter London airport is only 1 weekly, it would be a scheduled link none the less and hence a 3rd London route. (Last time this happened was when LGW/LHR/STN were all served).
Strange turn of events considering the contraction of the market in recent years (incidentally LHR-MAN recorded an increase this winter for the first time in ages).