date (s) conducted polling organisation / client conservatives labour liberal democrats others
0     23 - 25 april 2012     comres / evening standard           45%    36%                5%    13%
1     23 - 25 april 2012     comres / evening standard           54%    46%                 -      -
2     20 - 22 april 2012     yougov / evening standard           43%    41%                8%     9%
3     20 - 22 april 2012     yougov / evening standard           51%    49%                 -      -
4          19 april 2012                    tns - bmrb           45%    35%               11%     9%
5     13 - 15 april 2012     yougov / evening standard           45%    40%                7%     8%
6     13 - 15 april 2012     yougov / evening standard           53%    47%                 -      -
7       2 - 5 april 2012                        comres           47%    40%                6%     7%
8       2 - 5 april 2012                        comres           53%    47%                 -      -
9     12 - 15 march 2012                        yougov           49%    41%                5%     4%
10    12 - 15 march 2012                        yougov           54%    46%                 -      -
11  7 - 10 february 2012     yougov / evening standard           46%    45%                6%     3%
12  7 - 10 february 2012     yougov / evening standard           51%    49%                 -      -
13  19 - 21 january 2012                        comres           44%    46%                5%     5%
14  19 - 21 january 2012                        comres           49%    51%                 -      -
15  10 - 16 january 2012                        yougov           44%    46%                7%     3%
16  10 - 16 january 2012                        yougov           49%    51%                 -      -
17         november 2011     comres / evening standard           48%    40%                7%     4%
18       7 - 9 june 2011                        yougov           48%    41%                2%     9%
19            march 2011     comres / evening standard           36%    37%                5%     6%

Table as JSON:
{"date (s) conducted":{"0":"23 - 25 april 2012","1":"23 - 25 april 2012","2":"20 - 22 april 2012","3":"20 - 22 april 2012","4":"19 april 2012","5":"13 - 15 april 2012","6":"13 - 15 april 2012","7":"2 - 5 april 2012","8":"2 - 5 april 2012","9":"12 - 15 march 2012","10":"12 - 15 march 2012","11":"7 - 10 february 2012","12":"7 - 10 february 2012","13":"19 - 21 january 2012","14":"19 - 21 january 2012","15":"10 - 16 january 2012","16":"10 - 16 january 2012","17":"november 2011","18":"7 - 9 june 2011","19":"march 2011"},"polling organisation \/ client":{"0":"comres \/ evening standard","1":"comres \/ evening standard","2":"yougov \/ evening standard","3":"yougov \/ evening standard","4":"tns - bmrb","5":"yougov \/ evening standard","6":"yougov \/ evening standard","7":"comres","8":"comres","9":"yougov","10":"yougov","11":"yougov \/ evening standard","12":"yougov \/ evening standard","13":"comres","14":"comres","15":"yougov","16":"yougov","17":"comres \/ evening standard","18":"yougov","19":"comres \/ evening standard"},"conservatives":{"0":"45%","1":"54%","2":"43%","3":"51%","4":"45%","5":"45%","6":"53%","7":"47%","8":"53%","9":"49%","10":"54%","11":"46%","12":"51%","13":"44%","14":"49%","15":"44%","16":"49%","17":"48%","18":"48%","19":"36%"},"labour":{"0":"36%","1":"46%","2":"41%","3":"49%","4":"35%","5":"40%","6":"47%","7":"40%","8":"47%","9":"41%","10":"46%","11":"45%","12":"49%","13":"46%","14":"51%","15":"46%","16":"51%","17":"40%","18":"41%","19":"37%"},"liberal democrats":{"0":"5%","1":"-","2":"8%","3":"-","4":"11%","5":"7%","6":"-","7":"6%","8":"-","9":"5%","10":"-","11":"6%","12":"-","13":"5%","14":"-","15":"7%","16":"-","17":"7%","18":"2%","19":"5%"},"others":{"0":"13%","1":"-","2":"9%","3":"-","4":"9%","5":"8%","6":"-","7":"7%","8":"-","9":"4%","10":"-","11":"3%","12":"-","13":"5%","14":"-","15":"3%","16":"-","17":"4%","18":"9%","19":"6%"}}