A large scale disturbance (LSD) in plasma tail of comet Bradfield 1987s has been observed in some wide field photographs taken in the days 1987 October 19–20. A conspicuous plasma cloud moving along the tail axis is also visible. Wind-shock analysis shows that the LSD can be explained as the effect of a strong variation in the ecliptical polar component of solar wind speed. An analysis of solar activity suggests that the possible cause of the LSD is a solar burst occurred on 1987 October 16.4 (UT). Correlated geomagnetic effects are found on October 25–26 using corotation method. The plasma cloud seems to have a mean speed of 280 km s^–1.