I have deferred my State Pension, I see no point on paying extra tax on it when I am still in full-time employment and paying enough tax as it is! Also, for every year you defer your SP, they add another 10.4% to the amount they will eventually pay you - so in theory if you deferred it 10 years, you'd get nearly double in SP. I get a forecast every so often from them of what I'll expect to get when I do decide to retire.
In the NHS (my employer) you can retire and collect your pension, then have a short time off/less hours, then return to your job (provided your employer agrees), so yes, it's perfectly possible to have a job and a pension (or more than one pension)- it does whack you for tax though.
Don't forget you are exempt from NI when you reach retirement age, so you need to obtain an exemption certificate and give it to your payroll office.