The Conservative win upon its creation in 2000 was somewhat unexpected, as at that point, the entire area it covers (except for two Redbridge wards that fall under the Chingford and Woodford Green parliamentary seat) were represented by Labour MPs. However, the Romford and Upminster constituencies were among the very small number of seats that the Conservatives gained from Labour at the general election of 2001.
In line with this, and the 2005 general election result where those two parliamentary seats saw increased majorities, while the Conservatives gained the constituencies of Hornchurch and Ilford North from Labour, this seat became very safe for the Conservatives in the elections in 2004 and 2008. Indeed, in the 2008 election, they got more than twice as many votes as Labour.
The seat has, however, become extremely marginal following a swing of almost 12% to Labour in the 2012 election, which preluded Labour gaining a majority on Redbridge Council in 2014 for the first time since its creation and their regain of the Ilford North seat from the Conservatives at the 2015 general election. The seat became slightly more marginal in 2016, but it was not enough for Labour to gain it.