A transition detection circuit and method of operation of such a circuit are provided, the transition detection circuit having pulse generation circuitry to receive an input signal and to generate a pulse signal in response to a transition in the input signal, and pulse detection circuitry to assert an error signal on detection of the pulse signal generated by the pulse generation circuitry. The pulse generation circuitry has pulse control circuitry to control a property of the pulse signal dependent on a timing window indication signal. In particular, when the pulse signal is generated at least partly while the timing window indication signal is set, the pulse control circuitry controls the property of the pulse signal such that generated pulse signal is detected by the pulse detection circuitry. In contrast, when the pulse signal is entirely generated while the timing window indication signal is cleared, the pulse control circuitry controls the property of the pulse signal such that the generated pulse signal is undetected by the pulse detection circuitry. This gives rise to significant area and energy consumption savings, while still allowing reliable detection of timing errors.