C172 instructor pilot with student reported the left tank began leaking fuel after takeoff prompting the pilots to immediately return to the departure airport with ATC assistance.

Narrative

IP (Instructing Pilot) was scheduled with SP (Student Pilot) for PPC Flight Lesson. Pre-flight inspection revealed no defects with fuel drain valve or visible leaks around fuel tank area. SP and IP were aware of prior maintenance discrepancies relating to fuel leaks. After takeoff from Runway XX; IP noticed strong smell of fuel in cabin. Upon looking out the left side rear quarter window; IP noticed large quantity of fuel leaking from left tank streaming down left rear-quarter panel window down to the tail. Fuel was leaking from seam in wing at uncontrollable rate. At around 400 ft. MSL; IP took controls and notified ZZZ Tower of fuel leak. ZZZ Tower [requested priority handling]; asking for souls on board and prioritized landing. Other aircraft in the traffic pattern were given holding instructions. ATC gave option for Runway XY but IP opted for XX. IP flew a standard left traffic pattern at 1;100 feet MSL. IP landed without incident and was instructed to taxi back to ramp via [Taxiway] 1; 2; 3; 4. Airport Operations and ARFF (Airport Rescue and Firefighting) were dispatched and followed back to FBO ramp. Fuel leaked onto taxiway all the way back. IP expedited taxi and shut down immediately upon reaching suitable parking spot. Upon engine shut down; so much fuel was leaking that SP had to egress through IP-side door. Plane pushed back. Desiccant placed below leak per orders of airport operations crew. ARFF inspected aircraft and deemed it safe. Airport Operations requested that Maintenance be contacted due to actively leaking fuel tanks on ramp. Airport Operations took pictures of IP pilot certificates and driver's license for records. IP contacted on-duty A&P to notify of the incident.