A county is to cut 2,500 jobs over the next three years as it looks to save £685m over a nine-year campaign of savings.
Lancashire County Council has been told it will need to find an additional £233m of cutbacks by April 2020 to cover funding reductions from central government and growing demand for services.
While a reduction of 1,400 job posts was already planned at the town hall, new financial pressures mean it is now expected the loss of a further 1,100 jobs will be necessary by April 2018.
The latest financial plan delivered to cabinet means the local authority will have had to deliver savings of £685m between 2011 and 2020.
Lancashire will consult on proposals this winter before delivering final savings decisions in February 2016.
It expects the bulk of job reductions will be made on a voluntary basis and employees are being invited to apply for voluntary redundancy.
Cllr Jennifer Mein, leader of Lancashire County Council, said: 'These are the most challenging times for local government in living memory as we face the combination of severe central government cuts and rising demand for our services, particularly those serving vulnerable people.
'The scale of the challenge means that we are having to make ever more difficult decisions. We will do all that we can, but there is no doubt that the services we provide to our communities will have to be reduced in this period and people will notice the difference. Our priority will remain to protect the most vulnerable people in communities across Lancashire.
'Regrettably I'm also no longer confident we can reduce our workforce as much as we need to on a purely voluntary basis.'