Use two 2 way switches to create a two way switch system. There is a chance that if your house has these old wiring colours the switch drops may be from a loop in loop out radial lighting circuit done with junction boxes rather than ceiling roses as shown in fig 2.

Resources
2 way lighting circuit loop at switch. At the ceiling rose brown connects to loop as before black is now the switched line and the third grey wire is connected to. Two way light switch using 3 core cable. The switch wiring is all the same but the switch wire cable c leads up to a different set up. This is a loop in method which can be useful where the light fitting only has three terminals or when using downlighters. The in cable supplies power from the previous light or consumer unit. Logically it cant be done as both switches would need to be on for the circuit to work power the bulb that is but a two way switch system means that either switch should be able to turn on the bulb.
By wiring a 2 way switch the circuit below shows the basic concept of electricity flow to the load. The principle is exactly the same as when looping at the ceiling rose or using a junction box. Lets assume the load you are controlling is a light. Two way light switching schematic using a two wire control. There are different ways to connect up two way lighting circuits if it is a new installation the ideal way is to use a three core earth cable between the two light switches. If you are doing a new install or replacing a two way switch system go for the three wire control method.
Connect a new cable to the switch to provide power to the new light fitting. Lighting circuits loop at the switch. Loop at the switch. 4 wonder why you couldnt work that out yourself. The twin and earth switch cable has been replaced with a 3 core and earth cable. 2 see how it works.
The electricity flows from the hot wire black through the 2 way switch shown in off position and then to the light and returns through the neutral wire white. 1 look at diagrams of 2 way switching when the loop circuit runs through the ceiling and only the phase goes to and from the switch network. 3 think how little it changes if neutral also goes to and from the switch network. This is a completed circuit. Replace the one gang switch with a two gang switch. 2 way light switch wiring 3 wire.
You are most likely to see this 2 way lighting circuit in an industrialcommercial setting where the installation is trunkingconduit based and single core conductors are used. When i say 2 way swithces i mean a switch with two copper screws.