Shadow attorney general Catherine McKinnell has resigned from the shadow cabinet, citing concerns over Labour’s direction under Jeremy Corbyn.

Ms McKinnell said Labour was heading down an “increasingly negative path” amid “internal conflict” stemming from the recent shadow cabinet reshuffle.

With a “heavy heart”, she said she had concluded she could better serve the party from the backbenches.

She is the fourth MP to quit the front bench since Mr Corbyn’s reshuffle.

Just hours before her resignation, Mr Corbyn claimed the party was “moving on” from the internal ructions of recent weeks.

Last week’s reshuffle saw the exit of shadow Europe minister Pat McFadden and former culture secretary Michael Dugher – two critics of the leader – and the demotion of shadow defence secretary Maria Eagle to culture spokeswomen. Three other shadow ministers resigned in protest at the changes.

In her resignation letter, Ms McKinnell said being in the shadow cabinet had prevented her from speaking up on issues of importance to her constituents and that she felt she could serve them better as a backbencher.