The number of complaints about Lancashire Police rose last year by 13 per cent, new figures reveal.
The Independent Police Complaints Commission, said it is “concerned” by the figures.
Nationally, complaints rose 15 per cent, which it said was due to a change in the way complaints are recorded.
During the 2013/14 year, Lancashire Police upheld just four per cent of complaints lodged by members of the public – compared to 50 per cent of complaints investigated by the IPCC.
The watchdog said the low number of complaints being upheld following in-house reviews risks undermining public confidence.
IPCC chairman Dame Anne Owers said: “It is clear from these statistics that forces still struggle to get it right first time, and there are now serious questions about whether they get it right the second time either.
“We urgently need radical reforms to the system as a whole, to make it more accessible and straightforward, and to strengthen independent oversight.”
The figures show Lancashire Police received 877 complaints last year, up from 773 in the previous 12 months. These included 1,623 allegations –a 17 per cent rise on the year before.
It equates to 265 allegations for every 1,000 employees, slightly above the national average of 251.
The force completed 77 appeals in that time, upholding just three. However, the IPCC upheld half of the 106 appeals it completed relating to Lancashire Police.
Lancashire Police said it was committed to maintaining high standards and it was “never complacent” with feedback from the public.
A spokesman said: “We recognise that meeting the expectations of the public with whom we deal is critical to maintaining public confidence. Officers have thousands of such interactions each day and most end well. Where there are instances of professional standards falling short, it’s imperative to find out why and put it right.”