Every employer with at least one member of staff now has now additional responsibilities in the form providing a workplace pension scheme and contributing towards it. This is called automatic enrolment. The start date for getting the pension in place depends on the number of employees that a business employs. For small businesses the following table provides the staging date or the start date:

Number of employees Staging date
160-249 01-Apr-14
90-159 01-May-14
62-89 01-Jul-14
61 01-Aug-14
60 01-Oct-14
59 01-Nov-14
58 01-Jan-15
54-57 01-Mar-15
50-53 01-Apr-15
40-49 01-Aug-15
30-39 01-Oct-15

For those employing less than 30 employees the staging date is linked their PAYE codes as explained below.Fewer than 30 employees with the last 2 characters in their PAYE reference numbers:
92, A1-A9, B1-B9, AA-AZ, BA-BW, M1-M9, MA-MZ, Z1-Z9, ZA-ZZ , 0A-0Z, 1A-1Z or 2A-2Z – 01-Jun-15
BX – 01-Jul-15
BY – 01-Sep-15
BZ – 01-Nov-15
02-04, C1-C9, D1-D9, CA-CZ or DA-DZ – 01-Jan-16
00 05-07, E1-E9 or EA-EZ – 01-Feb-16
01, 08-11, F1-F9, G1-G9, FA-FZ or GA-GZ – 01-Mar-16
12-16, 3A-3Z, H1-H9 or HA-HZ – 01-Apr-16
I1-I9 or IA-IZ – 01-May-16
17-22, 4A-4Z, J1-J9 or JA-JZ – 01-Jun-16
23-29, 5A-5Z, K1-K9 or KA-KZ – 01-Jul-16
30-37, 6A-6Z, L1-L9 or LA-LZ – 01-Aug-16
N1-N9 or NA-NZ – 01-Sep-16
38-46, 7A-7Z, O1-O9 or OA-OZ – 01-Oct-16
47-57, 8A-8Z, Q1-Q9, R1-R9, S1-S9, T1-T9, QA-QZ, RA-RZ, SA-SZ or TA-TZ – 01-Nov-16
58-69, 9A-9Z, U1-U9, V1-V9, W1-W9, UA-UZ, VA-VZ or WA-WZ – 01-Jan-17
70-83, X1-X9, Y1-Y9, XA-XZ or YA-YZ – 01-Feb-17
P1-P9 or PA-PZ – 01-Mar-17
84-91, 93-99 – 01-Apr-17
Fewer than 30 unless otherwise described – 01-Apr-17

For new employers the staging dating will be as follows:
New employer (PAYE income first payable between 1 April 2012 and 31 March 2013) – 01-May-17
New employer (PAYE income first payable between 1 April 2013 and 31 March 2014) – 01-Jul-17
New employer (PAYE income first payable between 1 April 2014 and 31 March 2015) – 01-Aug-17
New employer (PAYE income first payable between 1 April 2015 and 31 December 2015) – 01-Oct-17
New employer (PAYE income first payable between 1 January 2016 and 30 September 2016) – 01-Nov-17
New employer (PAYE income first payable between 1 October 2016 and 30 June 2017) – 01-Jan-18
New employer (PAYE income first payable between 1 July 2017 and 30 September 2017) – 01-Feb-18

More information on auto enrolment could be found here